SWMM-USERS Digest - 25 Nov 2009 to 26 Nov 2009 (#2009-124)
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There are 5 messages totalling 1653 lines in this issue.
Topics of the day:
1. orifice in SWMM5 (5)
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Date: Thu, 26 Nov 2009 11:49:21 +0100
From: Maurizio Cingi <mrz...@GMAIL.COM>
Subject: orifice in SWMM5
I've found a problem using orifices in SWMM5 (5.0.018) .
In the attacched model you can see that the orice flow becomes unstable when
water height on both sides is between top and bottom of the orifice.
Then, when the orifice is completely submerged, the flow is stable at 0.5
cms (the correct value).
With a weir instead of orefice there isn't any problem.
Another problem: the volume in storage 02 increases less than the
OrificeFlow*timestep ( Q* dt ) and generates a big (huge) continuity error.
Best regards
M.Cingi
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
orifice_BUG.inp
[TITLE]
[OPTIONS]
FLOW_UNITS CMS
INFILTRATION HORTON
FLOW_ROUTING DYNWAVE
START_DATE 11/25/2009
START_TIME 00:00:00
REPORT_START_DATE 11/25/2009
REPORT_START_TIME 00:00:00
END_DATE 11/25/2009
END_TIME 00:10:00
SWEEP_START 01/01
SWEEP_END 12/31
DRY_DAYS 0
REPORT_STEP 00:00:01
WET_STEP 00:05:00
DRY_STEP 01:00:00
ROUTING_STEP 0:00:01
ALLOW_PONDING NO
INERTIAL_DAMPING PARTIAL
VARIABLE_STEP 0.75
LENGTHENING_STEP 0
MIN_SURFAREA 0
NORMAL_FLOW_LIMITED BOTH
SKIP_STEADY_STATE NO
FORCE_MAIN_EQUATION H-W
LINK_OFFSETS DEPTH
MIN_SLOPE 0
[EVAPORATION]
;;Type Parameters
;;---------- ----------
CONSTANT 0.0
[OUTFALLS]
;; Invert Outfall Stage/Table Tide
;;Name Elev. Type Time Series Gate
;;-------------- ---------- ---------- ---------------- ----
0 0 FREE NO
[STORAGE]
;; Invert Max. Init. Storage
Curve Ponded Evap.
;;Name Elev. Depth Depth Curve
Params Area Frac. Infiltration Parameters
;;-------------- -------- -------- -------- ---------- -------- --------
-------- -------- -------- -----------------------
O1 0 5 0 FUNCTIONAL 50 0
0 0 0
O2 0 5 0 FUNCTIONAL 50 0
0 0 0
W1 0 5 0 FUNCTIONAL 50 0
0 0 0
W2 0 5 0 FUNCTIONAL 50 0
0 0 0
[ORIFICES]
;; Inlet Outlet Orifice Crest
Disch. Flap Open/Close
;;Name Node Node Type Height
Coeff. Gate Time
;;-------------- ---------------- ---------------- ------------ ----------
---------- ---- ----------
ORIFICE O1 O2 SIDE .5
0.65 NO 0
[WEIRS]
;; Inlet Outlet Weir Crest
Disch. Flap End End
;;Name Node Node Type Height
Coeff. Gate Con. Coeff.
;;-------------- ---------------- ---------------- ------------ ----------
---------- ---- -------- ----------
WEIR W1 W2 TRANSVERSE 0.5
1.84 NO 0 0
[XSECTIONS]
;;Link Shape Geom1 Geom2 Geom3
Geom4 Barrels
;;-------------- ------------ ---------------- ---------- ----------
---------- ----------
ORIFICE RECT_CLOSED 1 1 0 0
WEIR RECT_OPEN 1 1 0
0
[DWF]
;; Average Time
;;Node Parameter Value Patterns
;;-------------- ---------------- ---------- ----------
O1 FLOW 1.0 "" ""
W1 FLOW 1.0 "" ""
[REPORT]
INPUT NO
CONTROLS NO
SUBCATCHMENTS ALL
NODES ALL
LINKS ALL
[TAGS]
[MAP]
DIMENSIONS 0.000 0.000 10000.000 10000.000
Units None
[COORDINATES]
;;Node X-Coord Y-Coord
;;-------------- ------------------ ------------------
0 5810.185 5586.420
O1 964.506 5000.000
O2 3973.765 4984.568
W1 1010.802 5987.654
W2 4050.926 6003.086
[VERTICES]
;;Link X-Coord Y-Coord
;;-------------- ------------------ ------------------
**********************************************************
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* In the body of the message type: signoff swmm-users *
**********************************************************
------------------------------
Date: Thu, 26 Nov 2009 07:40:00 -0700
From: Robert Dickinson <Robert.E....@US.MWHGLOBAL.COM>
Subject: Re: orifice in SWMM5
Hi Maurizio,
1st Thank you for a very interesting example file,
2nd You can eliminate the continuity error at the downstream node of your o=
riice if you run the model for 1 hour instead of 10 minutes,
3rd The equations for orifice flow and weir flow are different and the weir=
switches to an orifice flow equation when the depth is above the crown of =
the weir or the weir is surcharged. In effect in your model you are compar=
ing a larger orifice for the surcharged weir and a smaller orifice for the =
surcharged orifice.
4th If you plot the weir and orifice flow together on a one run you can see=
the effect of the smaller orifice - the flow is delayed by 15 minutes.
5th If you use the SWMM 5 Statistics Tool on the Weir and Orifice for any l=
ength run you will see that the total flow through the Weir and Orifice hav=
e the same volume.
6th We should still investigate however, why a shorter model run shows an a=
pparent continuity error at the downstream storage node, and finally
7th You model is atypical because it does not have any active outfalls but =
only ending storage nodes.
I hope this helps.
Robert E Dickinson
SW/WW Technical Engineering Specialist
MWH Soft, Inc
9340 Pontiac Drive Tel: 813-712-0664
Tampa, Florida, 33626 Alt: 813-494-2919
USA
robert.d...@mwhsoft.com
www.mwhsoft.com
-----Original Message-----
From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf Of Maur=
izio Cingi
Sent: Thursday, November 26, 2009 5:49 AM
To: SWMM-...@listserv.uoguelph.ca
Subject: [SWMM-USERS] orifice in SWMM5
I've found a problem using orifices in SWMM5 (5.0.018) .
In the attacched model you can see that the orice flow becomes unstable whe=
n
water height on both sides is between top and bottom of the orifice.
Then, when the orifice is completely submerged, the flow is stable at 0.5
cms (the correct value).
With a weir instead of orefice there isn't any problem.
Another problem: the volume in storage 02 increases less than the
OrificeFlow*timestep ( Q* dt ) and generates a big (huge) continuity error=
.
Best regards
M.Cingi
---------------------------------------------------------------------------=
---------------------------------------------------------------------------=
------------------------------------------------------------
orifice_BUG.inp
[TITLE]
[OPTIONS]
FLOW_UNITS CMS
INFILTRATION HORTON
FLOW_ROUTING DYNWAVE
START_DATE 11/25/2009
START_TIME 00:00:00
REPORT_START_DATE 11/25/2009
REPORT_START_TIME 00:00:00
END_DATE 11/25/2009
END_TIME 00:10:00
SWEEP_START 01/01
SWEEP_END 12/31
DRY_DAYS 0
REPORT_STEP 00:00:01
WET_STEP 00:05:00
DRY_STEP 01:00:00
ROUTING_STEP 0:00:01
ALLOW_PONDING NO
INERTIAL_DAMPING PARTIAL
VARIABLE_STEP 0.75
LENGTHENING_STEP 0
MIN_SURFAREA 0
NORMAL_FLOW_LIMITED BOTH
SKIP_STEADY_STATE NO
FORCE_MAIN_EQUATION H-W
LINK_OFFSETS DEPTH
MIN_SLOPE 0
[EVAPORATION]
;;Type Parameters
;;---------- ----------
CONSTANT 0.0
[OUTFALLS]
;; Invert Outfall Stage/Table Tide
;;Name Elev. Type Time Series Gate
;;-------------- ---------- ---------- ---------------- ----
0 0 FREE NO
[STORAGE]
;; Invert Max. Init. Storage
Curve Ponded Evap.
;;Name Elev. Depth Depth Curve
Params Area Frac. Infiltration Parameters
;;-------------- -------- -------- -------- ---------- -------- --------
-------- -------- -------- -----------------------
O1 0 5 0 FUNCTIONAL 50 0
0 0 0
O2 0 5 0 FUNCTIONAL 50 0
0 0 0
W1 0 5 0 FUNCTIONAL 50 0
0 0 0
W2 0 5 0 FUNCTIONAL 50 0
0 0 0
[ORIFICES]
;; Inlet Outlet Orifice Crest
Disch. Flap Open/Close
;;Name Node Node Type Height
Coeff. Gate Time
;;-------------- ---------------- ---------------- ------------ ----------
---------- ---- ----------
ORIFICE O1 O2 SIDE .5
0.65 NO 0
[WEIRS]
;; Inlet Outlet Weir Crest
Disch. Flap End End
;;Name Node Node Type Height
Coeff. Gate Con. Coeff.
;;-------------- ---------------- ---------------- ------------ ----------
---------- ---- -------- ----------
WEIR W1 W2 TRANSVERSE 0.5
1.84 NO 0 0
[XSECTIONS]
;;Link Shape Geom1 Geom2 Geom3
Geom4 Barrels
;;-------------- ------------ ---------------- ---------- ----------
---------- ----------
ORIFICE RECT_CLOSED 1 1 0 0
WEIR RECT_OPEN 1 1 0
0
[DWF]
;; Average Time
;;Node Parameter Value Patterns
;;-------------- ---------------- ---------- ----------
O1 FLOW 1.0 "" ""
W1 FLOW 1.0 "" ""
[REPORT]
INPUT NO
CONTROLS NO
SUBCATCHMENTS ALL
NODES ALL
LINKS ALL
[TAGS]
[MAP]
DIMENSIONS 0.000 0.000 10000.000 10000.000
Units None
[COORDINATES]
;;Node X-Coord Y-Coord
;;-------------- ------------------ ------------------
0 5810.185 5586.420
O1 964.506 5000.000
O2 3973.765 4984.568
W1 1010.802 5987.654
W2 4050.926 6003.086
[VERTICES]
;;Link X-Coord Y-Coord
;;-------------- ------------------ ------------------
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------------------------------
Date: Thu, 26 Nov 2009 09:39:01 -0700
From: Larry Bodnaruk <bodn...@AE.CA>
Subject: Re: orifice in SWMM5
Bob, I don't agree with your recommendation to run the model for one hour to make the continuity error disappear. This does not solve the problem or reduce the continuity error and only masks it - it is only smaller in proportion to the overall volume, which is obviously greater if you run the model longer but it still exists in absolute terms and is a symptom of the instability problem.
.................................................................
Larry Bodnaruk, P.Eng.
Practice Leader - Water Resources
Associated Engineering Alberta Ltd.
1000 Associated Engineering Plaza
10909 Jasper Avenue
Edmonton, Alberta
Canada
T5J 5B9
Phone (780) 451-7666 office or (780) 969-6348 direct
Fax (780) 454-7698
>>> Robert Dickinson <Robert.E....@US.MWHGLOBAL.COM> 11/26/2009 7:40 AM >>>
Hi Maurizio,
1st Thank you for a very interesting example file,
2nd You can eliminate the continuity error at the downstream node of your oriice if you run the model for 1 hour instead of 10 minutes,
3rd The equations for orifice flow and weir flow are different and the weir switches to an orifice flow equation when the depth is above the crown of the weir or the weir is surcharged. In effect in your model you are comparing a larger orifice for the surcharged weir and a smaller orifice for the surcharged orifice.
4th If you plot the weir and orifice flow together on a one run you can see the effect of the smaller orifice - the flow is delayed by 15 minutes.
5th If you use the SWMM 5 Statistics Tool on the Weir and Orifice for any length run you will see that the total flow through the Weir and Orifice have the same volume.
6th We should still investigate however, why a shorter model run shows an apparent continuity error at the downstream storage node, and finally
7th You model is atypical because it does not have any active outfalls but only ending storage nodes.
I hope this helps.
Robert E Dickinson
SW/WW Technical Engineering Specialist
MWH Soft, Inc
9340 Pontiac Drive Tel: 813-712-0664
Tampa, Florida, 33626 Alt: 813-494-2919
USA
robert.d...@mwhsoft.com
www.mwhsoft.com
-----Original Message-----
From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf Of Maurizio Cingi
Sent: Thursday, November 26, 2009 5:49 AM
To: SWMM-...@listserv.uoguelph.ca
Subject: [SWMM-USERS] orifice in SWMM5
I've found a problem using orifices in SWMM5 (5.0.018) .
In the attacched model you can see that the orice flow becomes unstable when
water height on both sides is between top and bottom of the orifice.
Then, when the orifice is completely submerged, the flow is stable at 0.5
cms (the correct value).
With a weir instead of orefice there isn't any problem.
Another problem: the volume in storage 02 increases less than the
OrificeFlow*timestep ( Q* dt ) and generates a big (huge) continuity error.
Best regards
M.Cingi
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
orifice_BUG.inp
[TITLE]
[OPTIONS]
FLOW_UNITS CMS
INFILTRATION HORTON
FLOW_ROUTING DYNWAVE
START_DATE 11/25/2009
START_TIME 00:00:00
REPORT_START_DATE 11/25/2009
REPORT_START_TIME 00:00:00
END_DATE 11/25/2009
END_TIME 00:10:00
SWEEP_START 01/01
SWEEP_END 12/31
DRY_DAYS 0
REPORT_STEP 00:00:01
WET_STEP 00:05:00
DRY_STEP 01:00:00
ROUTING_STEP 0:00:01
ALLOW_PONDING NO
INERTIAL_DAMPING PARTIAL
VARIABLE_STEP 0.75
LENGTHENING_STEP 0
MIN_SURFAREA 0
NORMAL_FLOW_LIMITED BOTH
SKIP_STEADY_STATE NO
FORCE_MAIN_EQUATION H-W
LINK_OFFSETS DEPTH
MIN_SLOPE 0
[EVAPORATION]
;;Type Parameters
;;---------- ----------
CONSTANT 0.0
[OUTFALLS]
;; Invert Outfall Stage/Table Tide
;;Name Elev. Type Time Series Gate
;;-------------- ---------- ---------- ---------------- ----
0 0 FREE NO
[STORAGE]
;; Invert Max. Init. Storage
Curve Ponded Evap.
;;Name Elev. Depth Depth Curve
Params Area Frac. Infiltration Parameters
;;-------------- -------- -------- -------- ---------- -------- --------
-------- -------- -------- -----------------------
O1 0 5 0 FUNCTIONAL 50 0
0 0 0
O2 0 5 0 FUNCTIONAL 50 0
0 0 0
W1 0 5 0 FUNCTIONAL 50 0
0 0 0
W2 0 5 0 FUNCTIONAL 50 0
0 0 0
[ORIFICES]
;; Inlet Outlet Orifice Crest
Disch. Flap Open/Close
;;Name Node Node Type Height
Coeff. Gate Time
;;-------------- ---------------- ---------------- ------------ ----------
---------- ---- ----------
ORIFICE O1 O2 SIDE .5
0.65 NO 0
[WEIRS]
;; Inlet Outlet Weir Crest
Disch. Flap End End
;;Name Node Node Type Height
Coeff. Gate Con. Coeff.
;;-------------- ---------------- ---------------- ------------ ----------
---------- ---- -------- ----------
WEIR W1 W2 TRANSVERSE 0.5
1.84 NO 0 0
[XSECTIONS]
;;Link Shape Geom1 Geom2 Geom3
Geom4 Barrels
;;-------------- ------------ ---------------- ---------- ----------
---------- ----------
ORIFICE RECT_CLOSED 1 1 0 0
WEIR RECT_OPEN 1 1 0
0
[DWF]
;; Average Time
;;Node Parameter Value Patterns
;;-------------- ---------------- ---------- ----------
O1 FLOW 1.0 "" ""
W1 FLOW 1.0 "" ""
[REPORT]
INPUT NO
CONTROLS NO
SUBCATCHMENTS ALL
NODES ALL
LINKS ALL
[TAGS]
[MAP]
DIMENSIONS 0.000 0.000 10000.000 10000.000
Units None
[COORDINATES]
;;Node X-Coord Y-Coord
;;-------------- ------------------ ------------------
0 5810.185 5586.420
O1 964.506 5000.000
O2 3973.765 4984.568
W1 1010.802 5987.654
W2 4050.926 6003.086
[VERTICES]
;;Link X-Coord Y-Coord
;;-------------- ------------------ ------------------
**********************************************************
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**********************************************************
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------------------------------
Date: Thu, 26 Nov 2009 17:48:42 +0100
From: Maurizio Cingi <mrz...@GMAIL.COM>
Subject: Re: orifice in SWMM5
Hi Robert,
thank you for your kind reply.
Just a few comments:
about 2nd - the continuity error decrease with a longer run (as %) but it is
only an "error dilution". Observing data you can see that the error (during
first ten minutes) is the same, then, when storage is full, it stops but the
total volume increases (due to overflow) so error % is less.....
attacched file -> graphic with Storage O2 volume and volume calculated as
integration of Q*dt
5th flow throught orefice is near correct (average value on more than few
time steps) but awfully unstable. I know that it can be viewed as a mere
aestethic problem but it is a strange behavior compared to the weir
stability in the same condition.
attacched file -> graphic with flow throught orifice (from swmm at time step
and average on 20 seconds
7th I recognize my example is an atipical model: at the beginning it was a
tipical model, then I purged it to eliminate every unnecessary
device/detail.
MC
2009/11/26 Robert Dickinson <Robert.E....@us.mwhglobal.com>
> Hi Maurizio,
>
>
>
> 1st Thank you for a very interesting example file,
>
> 2nd You can eliminate the continuity error at the downstream node of your
> oriice if you run the model for 1 hour instead of 10 minutes,
>
> 3rd The equations for orifice flow and weir flow are different and the weir
> switches to an orifice flow equation when the depth is above the crown of
> the weir or the weir is surcharged. In effect in your model you are
> comparing a larger orifice for the surcharged weir and a smaller orifice for
> the surcharged orifice.
>
> 4th If you plot the weir and orifice flow together on a one run you can see
> the effect of the smaller orifice - the flow is delayed by 15 minutes.
>
> 5th If you use the SWMM 5 Statistics Tool on the Weir and Orifice for any
> length run you will see that the total flow through the Weir and Orifice
> have the same volume.
>
> 6th We should still investigate however, why a shorter model run shows an
> apparent continuity error at the downstream storage node, and finally
>
> 7th You model is atypical because it does not have any active outfalls but
> only ending storage nodes.
>
>
>
> I hope this helps.
>
>
>
> Robert E Dickinson
>
> SW/WW Technical Engineering Specialist
>
> MWH Soft, Inc
>
> 9340 Pontiac Drive Tel: 813-712-0664
>
> Tampa, Florida, 33626 Alt: 813-494-2919
>
> USA
>
> robert.d...@mwhsoft.com
>
> www.mwhsoft.com
>
>
>
> -----Original Message-----
> From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf Of
> Maurizio Cingi
> Sent: Thursday, November 26, 2009 5:49 AM
> To: SWMM-...@listserv.uoguelph.ca
> Subject: [SWMM-USERS] orifice in SWMM5
>
>
>
> I've found a problem using orifices in SWMM5 (5.0.018) .
>
> In the attacched model you can see that the orice flow becomes unstable
> when
>
> water height on both sides is between top and bottom of the orifice.
>
> Then, when the orifice is completely submerged, the flow is stable at 0.5
>
> cms (the correct value).
>
> With a weir instead of orefice there isn't any problem.
>
> Another problem: the volume in storage 02 increases less than the
>
> OrificeFlow*timestep ( Q* dt ) and generates a big (huge) continuity
> error.
>
>
>
> Best regards
>
> M.Cingi
>
>
> ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
>
>
>
> orifice_BUG.inp
>
> [TITLE]
>
>
>
> [OPTIONS]
>
> FLOW_UNITS CMS
>
> INFILTRATION HORTON
>
> FLOW_ROUTING DYNWAVE
>
> START_DATE 11/25/2009
>
> START_TIME 00:00:00
>
> REPORT_START_DATE 11/25/2009
>
> REPORT_START_TIME 00:00:00
>
> END_DATE 11/25/2009
>
> END_TIME 00:10:00
>
> SWEEP_START 01/01
>
> SWEEP_END 12/31
>
> DRY_DAYS 0
>
> REPORT_STEP 00:00:01
>
> WET_STEP 00:05:00
>
> DRY_STEP 01:00:00
>
> ROUTING_STEP 0:00:01
>
> ALLOW_PONDING NO
>
> INERTIAL_DAMPING PARTIAL
>
> VARIABLE_STEP 0.75
>
> LENGTHENING_STEP 0
>
> MIN_SURFAREA 0
>
> NORMAL_FLOW_LIMITED BOTH
>
> SKIP_STEADY_STATE NO
>
> FORCE_MAIN_EQUATION H-W
>
> LINK_OFFSETS DEPTH
>
> MIN_SLOPE 0
>
>
>
> [EVAPORATION]
>
> ;;Type Parameters
>
> ;;---------- ----------
>
> CONSTANT 0.0
>
>
>
> [OUTFALLS]
>
> ;; Invert Outfall Stage/Table Tide
>
> ;;Name Elev. Type Time Series Gate
>
> ;;-------------- ---------- ---------- ---------------- ----
>
> 0 0 FREE NO
>
>
>
> [STORAGE]
>
> ;; Invert Max. Init. Storage
>
> Curve Ponded Evap.
>
> ;;Name Elev. Depth Depth Curve
>
> Params Area Frac. Infiltration Parameters
>
> ;;-------------- -------- -------- -------- ---------- -------- --------
>
> -------- -------- -------- -----------------------
>
> O1 0 5 0 FUNCTIONAL 50 0
>
> 0 0 0
>
> O2 0 5 0 FUNCTIONAL 50 0
>
> 0 0 0
>
> W1 0 5 0 FUNCTIONAL 50 0
>
> 0 0 0
>
> W2 0 5 0 FUNCTIONAL 50 0
>
> 0 0 0
>
>
>
> [ORIFICES]
>
> ;; Inlet Outlet Orifice Crest
>
> Disch. Flap Open/Close
>
> ;;Name Node Node Type Height
>
> Coeff. Gate Time
>
> ;;-------------- ---------------- ---------------- ------------ ----------
>
> ---------- ---- ----------
>
> ORIFICE O1 O2 SIDE .5
>
> 0.65 NO 0
>
>
>
> [WEIRS]
>
> ;; Inlet Outlet Weir Crest
>
> Disch. Flap End End
>
> ;;Name Node Node Type Height
>
> Coeff. Gate Con. Coeff.
>
> ;;-------------- ---------------- ---------------- ------------ ----------
>
> ---------- ---- -------- ----------
>
> WEIR W1 W2 TRANSVERSE 0.5
>
> 1.84 NO 0 0
>
>
>
> [XSECTIONS]
>
> ;;Link Shape Geom1 Geom2 Geom3
>
> Geom4 Barrels
>
> ;;-------------- ------------ ---------------- ---------- ----------
>
> ---------- ----------
>
> ORIFICE RECT_CLOSED 1 1 0 0
>
> WEIR RECT_OPEN 1 1 0
>
> 0
>
>
>
> [DWF]
>
> ;; Average Time
>
> ;;Node Parameter Value Patterns
>
> ;;-------------- ---------------- ---------- ----------
>
> O1 FLOW 1.0 "" ""
>
> W1 FLOW 1.0 "" ""
>
>
>
> [REPORT]
>
> INPUT NO
>
> CONTROLS NO
>
> SUBCATCHMENTS ALL
>
> NODES ALL
>
> LINKS ALL
>
>
>
> [TAGS]
>
>
>
> [MAP]
>
> DIMENSIONS 0.000 0.000 10000.000 10000.000
>
> Units None
>
>
>
> [COORDINATES]
>
> ;;Node X-Coord Y-Coord
>
> ;;-------------- ------------------ ------------------
>
> 0 5810.185 5586.420
>
> O1 964.506 5000.000
>
> O2 3973.765 4984.568
>
> W1 1010.802 5987.654
>
> W2 4050.926 6003.086
>
>
>
> [VERTICES]
>
> ;;Link X-Coord Y-Coord
>
> ;;-------------- ------------------ ------------------
>
>
>
> **********************************************************
>
> * To sign off, email to: list...@listserv.uoguelph.ca *
>
> * In the body of the message type: signoff swmm-users *
>
> **********************************************************
>
>
>
> **********************************************************
> * To sign off, email to: list...@listserv.uoguelph.ca *
> * In the body of the message type: signoff swmm-users *
> **********************************************************
>
**********************************************************
* To sign off, email to: list...@listserv.uoguelph.ca *
* In the body of the message type: signoff swmm-users *
**********************************************************
------------------------------
Date: Thu, 26 Nov 2009 11:55:11 -0500
From: Robert E Dickinson <robert.d...@GMAIL.COM>
Subject: Re: orifice in SWMM5
Hi Larry,
That is a fair criticism and you are right that running the model longer
drives down the continuity error because the overall inflow and final
storage increases. However, the fact that the example model does not have
an outfall and simply a storage node as the downstream boundary condition is
affecting the stability of the orifice. The equation for the orifice flow
when both ends of the orifice are submerged and there is not outlet from the
model would tend to be unstable.
Best and Kind Regards,
Robert Edgar Dickinson
On Thu, Nov 26, 2009 at 11:39 AM, Larry Bodnaruk <bodn...@ae.ca> wrote:
> Bob, I don't agree with your recommendation to run the model for one hour
> to make the continuity error disappear. This does not solve the problem or
> reduce the continuity error and only masks it - it is only smaller in
> proportion to the overall volume, which is obviously greater if you run the
> model longer but it still exists in absolute terms and is a symptom of the
> instability problem.
>
> .................................................................
> Larry Bodnaruk, P.Eng.
> Practice Leader - Water Resources
> Associated Engineering Alberta Ltd.
> 1000 Associated Engineering Plaza
> 10909 Jasper Avenue
> Edmonton, Alberta
> Canada
> T5J 5B9
> Phone (780) 451-7666 office or (780) 969-6348 direct
> Fax (780) 454-7698
>
>
> >>> Robert Dickinson <Robert.E....@US.MWHGLOBAL.COM> 11/26/2009 7:40
> AM >>>
> Hi Maurizio,
>
>
>
> 1st Thank you for a very interesting example file,
>
> 2nd You can eliminate the continuity error at the downstream node of your
> oriice if you run the model for 1 hour instead of 10 minutes,
>
> 3rd The equations for orifice flow and weir flow are different and the weir
> switches to an orifice flow equation when the depth is above the crown of
> the weir or the weir is surcharged. In effect in your model you are
> comparing a larger orifice for the surcharged weir and a smaller orifice for
> the surcharged orifice.
>
> 4th If you plot the weir and orifice flow together on a one run you can see
> the effect of the smaller orifice - the flow is delayed by 15 minutes.
>
> 5th If you use the SWMM 5 Statistics Tool on the Weir and Orifice for any
> length run you will see that the total flow through the Weir and Orifice
> have the same volume.
>
> 6th We should still investigate however, why a shorter model run shows an
> apparent continuity error at the downstream storage node, and finally
>
> 7th You model is atypical because it does not have any active outfalls but
> only ending storage nodes.
>
>
>
> I hope this helps.
>
>
>
> Robert E Dickinson
>
> SW/WW Technical Engineering Specialist
>
> MWH Soft, Inc
>
> 9340 Pontiac Drive Tel: 813-712-0664
>
> Tampa, Florida, 33626 Alt: 813-494-2919
>
> USA
>
> robert.d...@mwhsoft.com
>
> www.mwhsoft.com
>
>
>
> -----Original Message-----
> From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf Of
> Maurizio Cingi
> Sent: Thursday, November 26, 2009 5:49 AM
> To: SWMM-...@listserv.uoguelph.ca
> Subject: [SWMM-USERS] orifice in SWMM5
>
>
>
> I've found a problem using orifices in SWMM5 (5.0.018) .
>
> In the attacched model you can see that the orice flow becomes unstable
> when
>
> water height on both sides is between top and bottom of the orifice.
>
> Then, when the orifice is completely submerged, the flow is stable at 0.5
>
> cms (the correct value).
>
> With a weir instead of orefice there isn't any problem.
>
> Another problem: the volume in storage 02 increases less than the
>
> OrificeFlow*timestep ( Q* dt ) and generates a big (huge) continuity
> error.
>
>
>
> Best regards
>
> M.Cingi
>
>
> ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
>
>
>
> orifice_BUG.inp
>
> [TITLE]
>
>
>
> [OPTIONS]
>
> FLOW_UNITS CMS
>
> INFILTRATION HORTON
>
> FLOW_ROUTING DYNWAVE
>
> START_DATE 11/25/2009
>
> START_TIME 00:00:00
>
> REPORT_START_DATE 11/25/2009
>
> REPORT_START_TIME 00:00:00
>
> END_DATE 11/25/2009
>
> END_TIME 00:10:00
>
> SWEEP_START 01/01
>
> SWEEP_END 12/31
>
> DRY_DAYS 0
>
> REPORT_STEP 00:00:01
>
> WET_STEP 00:05:00
>
> DRY_STEP 01:00:00
>
> ROUTING_STEP 0:00:01
>
> ALLOW_PONDING NO
>
> INERTIAL_DAMPING PARTIAL
>
> VARIABLE_STEP 0.75
>
> LENGTHENING_STEP 0
>
> MIN_SURFAREA 0
>
> NORMAL_FLOW_LIMITED BOTH
>
> SKIP_STEADY_STATE NO
>
> FORCE_MAIN_EQUATION H-W
>
> LINK_OFFSETS DEPTH
>
> MIN_SLOPE 0
>
>
>
> [EVAPORATION]
>
> ;;Type Parameters
>
> ;;---------- ----------
>
> CONSTANT 0.0
>
>
>
> [OUTFALLS]
>
> ;; Invert Outfall Stage/Table Tide
>
> ;;Name Elev. Type Time Series Gate
>
> ;;-------------- ---------- ---------- ---------------- ----
>
> 0 0 FREE NO
>
>
>
> [STORAGE]
>
> ;; Invert Max. Init. Storage
>
> Curve Ponded Evap.
>
> ;;Name Elev. Depth Depth Curve
>
> Params Area Frac. Infiltration Parameters
>
> ;;-------------- -------- -------- -------- ---------- -------- --------
>
> -------- -------- -------- -----------------------
>
> O1 0 5 0 FUNCTIONAL 50 0
>
> 0 0 0
>
> O2 0 5 0 FUNCTIONAL 50 0
>
> 0 0 0
>
> W1 0 5 0 FUNCTIONAL 50 0
>
> 0 0 0
>
> W2 0 5 0 FUNCTIONAL 50 0
>
> 0 0 0
>
>
>
> [ORIFICES]
>
> ;; Inlet Outlet Orifice Crest
>
> Disch. Flap Open/Close
>
> ;;Name Node Node Type Height
>
> Coeff. Gate Time
>
> ;;-------------- ---------------- ---------------- ------------ ----------
>
> ---------- ---- ----------
>
> ORIFICE O1 O2 SIDE .5
>
> 0.65 NO 0
>
>
>
> [WEIRS]
>
> ;; Inlet Outlet Weir Crest
>
> Disch. Flap End End
>
> ;;Name Node Node Type Height
>
> Coeff. Gate Con. Coeff.
>
> ;;-------------- ---------------- ---------------- ------------ ----------
>
> ---------- ---- -------- ----------
>
> WEIR W1 W2 TRANSVERSE 0.5
>
> 1.84 NO 0 0
>
>
>
> [XSECTIONS]
>
> ;;Link Shape Geom1 Geom2 Geom3
>
> Geom4 Barrels
>
> ;;-------------- ------------ ---------------- ---------- ----------
>
> ---------- ----------
>
> ORIFICE RECT_CLOSED 1 1 0 0
>
> WEIR RECT_OPEN 1 1 0
>
> 0
>
>
>
> [DWF]
>
> ;; Average Time
>
> ;;Node Parameter Value Patterns
>
> ;;-------------- ---------------- ---------- ----------
>
> O1 FLOW 1.0 "" ""
>
> W1 FLOW 1.0 "" ""
>
>
>
> [REPORT]
>
> INPUT NO
>
> CONTROLS NO
>
> SUBCATCHMENTS ALL
>
> NODES ALL
>
> LINKS ALL
>
>
>
> [TAGS]
>
>
>
> [MAP]
>
> DIMENSIONS 0.000 0.000 10000.000 10000.000
>
> Units None
>
>
>
> [COORDINATES]
>
> ;;Node X-Coord Y-Coord
>
> ;;-------------- ------------------ ------------------
>
> 0 5810.185 5586.420
>
> O1 964.506 5000.000
>
> O2 3973.765 4984.568
>
> W1 1010.802 5987.654
>
> W2 4050.926 6003.086
>
>
>
> [VERTICES]
>
> ;;Link X-Coord Y-Coord
>
> ;;-------------- ------------------ ------------------
>
>
>
> **********************************************************
>
> * To sign off, email to: list...@listserv.uoguelph.ca *
>
> * In the body of the message type: signoff swmm-users *
>
> **********************************************************
>
>
>
> **********************************************************
> * To sign off, email to: list...@listserv.uoguelph.ca *
> * In the body of the message type: signoff swmm-users *
> **********************************************************
>
> **********************************************************
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**********************************************************
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------------------------------
End of SWMM-USERS Digest - 25 Nov 2009 to 26 Nov 2009 (#2009-124)
*****************************************************************
Topics of the day:
1. orifice in SWMM5 (5)
**********************************************************
* To sign off, email to: list...@listserv.uoguelph.ca *
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**********************************************************
----------------------------------------------------------------------
Date: Thu, 26 Nov 2009 11:49:21 +0100
From: Maurizio Cingi <mrz...@GMAIL.COM>
Subject: orifice in SWMM5
I've found a problem using orifices in SWMM5 (5.0.018) .
In the attacched model you can see that the orice flow becomes unstable when
water height on both sides is between top and bottom of the orifice.
Then, when the orifice is completely submerged, the flow is stable at 0.5
cms (the correct value).
With a weir instead of orefice there isn't any problem.
Another problem: the volume in storage 02 increases less than the
OrificeFlow*timestep ( Q* dt ) and generates a big (huge) continuity error.
Best regards
M.Cingi
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
orifice_BUG.inp
[TITLE]
[OPTIONS]
FLOW_UNITS CMS
INFILTRATION HORTON
FLOW_ROUTING DYNWAVE
START_DATE 11/25/2009
START_TIME 00:00:00
REPORT_START_DATE 11/25/2009
REPORT_START_TIME 00:00:00
END_DATE 11/25/2009
END_TIME 00:10:00
SWEEP_START 01/01
SWEEP_END 12/31
DRY_DAYS 0
REPORT_STEP 00:00:01
WET_STEP 00:05:00
DRY_STEP 01:00:00
ROUTING_STEP 0:00:01
ALLOW_PONDING NO
INERTIAL_DAMPING PARTIAL
VARIABLE_STEP 0.75
LENGTHENING_STEP 0
MIN_SURFAREA 0
NORMAL_FLOW_LIMITED BOTH
SKIP_STEADY_STATE NO
FORCE_MAIN_EQUATION H-W
LINK_OFFSETS DEPTH
MIN_SLOPE 0
[EVAPORATION]
;;Type Parameters
;;---------- ----------
CONSTANT 0.0
[OUTFALLS]
;; Invert Outfall Stage/Table Tide
;;Name Elev. Type Time Series Gate
;;-------------- ---------- ---------- ---------------- ----
0 0 FREE NO
[STORAGE]
;; Invert Max. Init. Storage
Curve Ponded Evap.
;;Name Elev. Depth Depth Curve
Params Area Frac. Infiltration Parameters
;;-------------- -------- -------- -------- ---------- -------- --------
-------- -------- -------- -----------------------
O1 0 5 0 FUNCTIONAL 50 0
0 0 0
O2 0 5 0 FUNCTIONAL 50 0
0 0 0
W1 0 5 0 FUNCTIONAL 50 0
0 0 0
W2 0 5 0 FUNCTIONAL 50 0
0 0 0
[ORIFICES]
;; Inlet Outlet Orifice Crest
Disch. Flap Open/Close
;;Name Node Node Type Height
Coeff. Gate Time
;;-------------- ---------------- ---------------- ------------ ----------
---------- ---- ----------
ORIFICE O1 O2 SIDE .5
0.65 NO 0
[WEIRS]
;; Inlet Outlet Weir Crest
Disch. Flap End End
;;Name Node Node Type Height
Coeff. Gate Con. Coeff.
;;-------------- ---------------- ---------------- ------------ ----------
---------- ---- -------- ----------
WEIR W1 W2 TRANSVERSE 0.5
1.84 NO 0 0
[XSECTIONS]
;;Link Shape Geom1 Geom2 Geom3
Geom4 Barrels
;;-------------- ------------ ---------------- ---------- ----------
---------- ----------
ORIFICE RECT_CLOSED 1 1 0 0
WEIR RECT_OPEN 1 1 0
0
[DWF]
;; Average Time
;;Node Parameter Value Patterns
;;-------------- ---------------- ---------- ----------
O1 FLOW 1.0 "" ""
W1 FLOW 1.0 "" ""
[REPORT]
INPUT NO
CONTROLS NO
SUBCATCHMENTS ALL
NODES ALL
LINKS ALL
[TAGS]
[MAP]
DIMENSIONS 0.000 0.000 10000.000 10000.000
Units None
[COORDINATES]
;;Node X-Coord Y-Coord
;;-------------- ------------------ ------------------
0 5810.185 5586.420
O1 964.506 5000.000
O2 3973.765 4984.568
W1 1010.802 5987.654
W2 4050.926 6003.086
[VERTICES]
;;Link X-Coord Y-Coord
;;-------------- ------------------ ------------------
**********************************************************
* To sign off, email to: list...@listserv.uoguelph.ca *
* In the body of the message type: signoff swmm-users *
**********************************************************
------------------------------
Date: Thu, 26 Nov 2009 07:40:00 -0700
From: Robert Dickinson <Robert.E....@US.MWHGLOBAL.COM>
Subject: Re: orifice in SWMM5
Hi Maurizio,
1st Thank you for a very interesting example file,
2nd You can eliminate the continuity error at the downstream node of your o=
riice if you run the model for 1 hour instead of 10 minutes,
3rd The equations for orifice flow and weir flow are different and the weir=
switches to an orifice flow equation when the depth is above the crown of =
the weir or the weir is surcharged. In effect in your model you are compar=
ing a larger orifice for the surcharged weir and a smaller orifice for the =
surcharged orifice.
4th If you plot the weir and orifice flow together on a one run you can see=
the effect of the smaller orifice - the flow is delayed by 15 minutes.
5th If you use the SWMM 5 Statistics Tool on the Weir and Orifice for any l=
ength run you will see that the total flow through the Weir and Orifice hav=
e the same volume.
6th We should still investigate however, why a shorter model run shows an a=
pparent continuity error at the downstream storage node, and finally
7th You model is atypical because it does not have any active outfalls but =
only ending storage nodes.
I hope this helps.
Robert E Dickinson
SW/WW Technical Engineering Specialist
MWH Soft, Inc
9340 Pontiac Drive Tel: 813-712-0664
Tampa, Florida, 33626 Alt: 813-494-2919
USA
robert.d...@mwhsoft.com
www.mwhsoft.com
-----Original Message-----
From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf Of Maur=
izio Cingi
Sent: Thursday, November 26, 2009 5:49 AM
To: SWMM-...@listserv.uoguelph.ca
Subject: [SWMM-USERS] orifice in SWMM5
I've found a problem using orifices in SWMM5 (5.0.018) .
In the attacched model you can see that the orice flow becomes unstable whe=
n
water height on both sides is between top and bottom of the orifice.
Then, when the orifice is completely submerged, the flow is stable at 0.5
cms (the correct value).
With a weir instead of orefice there isn't any problem.
Another problem: the volume in storage 02 increases less than the
OrificeFlow*timestep ( Q* dt ) and generates a big (huge) continuity error=
.
Best regards
M.Cingi
---------------------------------------------------------------------------=
---------------------------------------------------------------------------=
------------------------------------------------------------
orifice_BUG.inp
[TITLE]
[OPTIONS]
FLOW_UNITS CMS
INFILTRATION HORTON
FLOW_ROUTING DYNWAVE
START_DATE 11/25/2009
START_TIME 00:00:00
REPORT_START_DATE 11/25/2009
REPORT_START_TIME 00:00:00
END_DATE 11/25/2009
END_TIME 00:10:00
SWEEP_START 01/01
SWEEP_END 12/31
DRY_DAYS 0
REPORT_STEP 00:00:01
WET_STEP 00:05:00
DRY_STEP 01:00:00
ROUTING_STEP 0:00:01
ALLOW_PONDING NO
INERTIAL_DAMPING PARTIAL
VARIABLE_STEP 0.75
LENGTHENING_STEP 0
MIN_SURFAREA 0
NORMAL_FLOW_LIMITED BOTH
SKIP_STEADY_STATE NO
FORCE_MAIN_EQUATION H-W
LINK_OFFSETS DEPTH
MIN_SLOPE 0
[EVAPORATION]
;;Type Parameters
;;---------- ----------
CONSTANT 0.0
[OUTFALLS]
;; Invert Outfall Stage/Table Tide
;;Name Elev. Type Time Series Gate
;;-------------- ---------- ---------- ---------------- ----
0 0 FREE NO
[STORAGE]
;; Invert Max. Init. Storage
Curve Ponded Evap.
;;Name Elev. Depth Depth Curve
Params Area Frac. Infiltration Parameters
;;-------------- -------- -------- -------- ---------- -------- --------
-------- -------- -------- -----------------------
O1 0 5 0 FUNCTIONAL 50 0
0 0 0
O2 0 5 0 FUNCTIONAL 50 0
0 0 0
W1 0 5 0 FUNCTIONAL 50 0
0 0 0
W2 0 5 0 FUNCTIONAL 50 0
0 0 0
[ORIFICES]
;; Inlet Outlet Orifice Crest
Disch. Flap Open/Close
;;Name Node Node Type Height
Coeff. Gate Time
;;-------------- ---------------- ---------------- ------------ ----------
---------- ---- ----------
ORIFICE O1 O2 SIDE .5
0.65 NO 0
[WEIRS]
;; Inlet Outlet Weir Crest
Disch. Flap End End
;;Name Node Node Type Height
Coeff. Gate Con. Coeff.
;;-------------- ---------------- ---------------- ------------ ----------
---------- ---- -------- ----------
WEIR W1 W2 TRANSVERSE 0.5
1.84 NO 0 0
[XSECTIONS]
;;Link Shape Geom1 Geom2 Geom3
Geom4 Barrels
;;-------------- ------------ ---------------- ---------- ----------
---------- ----------
ORIFICE RECT_CLOSED 1 1 0 0
WEIR RECT_OPEN 1 1 0
0
[DWF]
;; Average Time
;;Node Parameter Value Patterns
;;-------------- ---------------- ---------- ----------
O1 FLOW 1.0 "" ""
W1 FLOW 1.0 "" ""
[REPORT]
INPUT NO
CONTROLS NO
SUBCATCHMENTS ALL
NODES ALL
LINKS ALL
[TAGS]
[MAP]
DIMENSIONS 0.000 0.000 10000.000 10000.000
Units None
[COORDINATES]
;;Node X-Coord Y-Coord
;;-------------- ------------------ ------------------
0 5810.185 5586.420
O1 964.506 5000.000
O2 3973.765 4984.568
W1 1010.802 5987.654
W2 4050.926 6003.086
[VERTICES]
;;Link X-Coord Y-Coord
;;-------------- ------------------ ------------------
**********************************************************
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**********************************************************
**********************************************************
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**********************************************************
------------------------------
Date: Thu, 26 Nov 2009 09:39:01 -0700
From: Larry Bodnaruk <bodn...@AE.CA>
Subject: Re: orifice in SWMM5
Bob, I don't agree with your recommendation to run the model for one hour to make the continuity error disappear. This does not solve the problem or reduce the continuity error and only masks it - it is only smaller in proportion to the overall volume, which is obviously greater if you run the model longer but it still exists in absolute terms and is a symptom of the instability problem.
.................................................................
Larry Bodnaruk, P.Eng.
Practice Leader - Water Resources
Associated Engineering Alberta Ltd.
1000 Associated Engineering Plaza
10909 Jasper Avenue
Edmonton, Alberta
Canada
T5J 5B9
Phone (780) 451-7666 office or (780) 969-6348 direct
Fax (780) 454-7698
>>> Robert Dickinson <Robert.E....@US.MWHGLOBAL.COM> 11/26/2009 7:40 AM >>>
Hi Maurizio,
1st Thank you for a very interesting example file,
2nd You can eliminate the continuity error at the downstream node of your oriice if you run the model for 1 hour instead of 10 minutes,
3rd The equations for orifice flow and weir flow are different and the weir switches to an orifice flow equation when the depth is above the crown of the weir or the weir is surcharged. In effect in your model you are comparing a larger orifice for the surcharged weir and a smaller orifice for the surcharged orifice.
4th If you plot the weir and orifice flow together on a one run you can see the effect of the smaller orifice - the flow is delayed by 15 minutes.
5th If you use the SWMM 5 Statistics Tool on the Weir and Orifice for any length run you will see that the total flow through the Weir and Orifice have the same volume.
6th We should still investigate however, why a shorter model run shows an apparent continuity error at the downstream storage node, and finally
7th You model is atypical because it does not have any active outfalls but only ending storage nodes.
I hope this helps.
Robert E Dickinson
SW/WW Technical Engineering Specialist
MWH Soft, Inc
9340 Pontiac Drive Tel: 813-712-0664
Tampa, Florida, 33626 Alt: 813-494-2919
USA
robert.d...@mwhsoft.com
www.mwhsoft.com
-----Original Message-----
From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf Of Maurizio Cingi
Sent: Thursday, November 26, 2009 5:49 AM
To: SWMM-...@listserv.uoguelph.ca
Subject: [SWMM-USERS] orifice in SWMM5
I've found a problem using orifices in SWMM5 (5.0.018) .
In the attacched model you can see that the orice flow becomes unstable when
water height on both sides is between top and bottom of the orifice.
Then, when the orifice is completely submerged, the flow is stable at 0.5
cms (the correct value).
With a weir instead of orefice there isn't any problem.
Another problem: the volume in storage 02 increases less than the
OrificeFlow*timestep ( Q* dt ) and generates a big (huge) continuity error.
Best regards
M.Cingi
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
orifice_BUG.inp
[TITLE]
[OPTIONS]
FLOW_UNITS CMS
INFILTRATION HORTON
FLOW_ROUTING DYNWAVE
START_DATE 11/25/2009
START_TIME 00:00:00
REPORT_START_DATE 11/25/2009
REPORT_START_TIME 00:00:00
END_DATE 11/25/2009
END_TIME 00:10:00
SWEEP_START 01/01
SWEEP_END 12/31
DRY_DAYS 0
REPORT_STEP 00:00:01
WET_STEP 00:05:00
DRY_STEP 01:00:00
ROUTING_STEP 0:00:01
ALLOW_PONDING NO
INERTIAL_DAMPING PARTIAL
VARIABLE_STEP 0.75
LENGTHENING_STEP 0
MIN_SURFAREA 0
NORMAL_FLOW_LIMITED BOTH
SKIP_STEADY_STATE NO
FORCE_MAIN_EQUATION H-W
LINK_OFFSETS DEPTH
MIN_SLOPE 0
[EVAPORATION]
;;Type Parameters
;;---------- ----------
CONSTANT 0.0
[OUTFALLS]
;; Invert Outfall Stage/Table Tide
;;Name Elev. Type Time Series Gate
;;-------------- ---------- ---------- ---------------- ----
0 0 FREE NO
[STORAGE]
;; Invert Max. Init. Storage
Curve Ponded Evap.
;;Name Elev. Depth Depth Curve
Params Area Frac. Infiltration Parameters
;;-------------- -------- -------- -------- ---------- -------- --------
-------- -------- -------- -----------------------
O1 0 5 0 FUNCTIONAL 50 0
0 0 0
O2 0 5 0 FUNCTIONAL 50 0
0 0 0
W1 0 5 0 FUNCTIONAL 50 0
0 0 0
W2 0 5 0 FUNCTIONAL 50 0
0 0 0
[ORIFICES]
;; Inlet Outlet Orifice Crest
Disch. Flap Open/Close
;;Name Node Node Type Height
Coeff. Gate Time
;;-------------- ---------------- ---------------- ------------ ----------
---------- ---- ----------
ORIFICE O1 O2 SIDE .5
0.65 NO 0
[WEIRS]
;; Inlet Outlet Weir Crest
Disch. Flap End End
;;Name Node Node Type Height
Coeff. Gate Con. Coeff.
;;-------------- ---------------- ---------------- ------------ ----------
---------- ---- -------- ----------
WEIR W1 W2 TRANSVERSE 0.5
1.84 NO 0 0
[XSECTIONS]
;;Link Shape Geom1 Geom2 Geom3
Geom4 Barrels
;;-------------- ------------ ---------------- ---------- ----------
---------- ----------
ORIFICE RECT_CLOSED 1 1 0 0
WEIR RECT_OPEN 1 1 0
0
[DWF]
;; Average Time
;;Node Parameter Value Patterns
;;-------------- ---------------- ---------- ----------
O1 FLOW 1.0 "" ""
W1 FLOW 1.0 "" ""
[REPORT]
INPUT NO
CONTROLS NO
SUBCATCHMENTS ALL
NODES ALL
LINKS ALL
[TAGS]
[MAP]
DIMENSIONS 0.000 0.000 10000.000 10000.000
Units None
[COORDINATES]
;;Node X-Coord Y-Coord
;;-------------- ------------------ ------------------
0 5810.185 5586.420
O1 964.506 5000.000
O2 3973.765 4984.568
W1 1010.802 5987.654
W2 4050.926 6003.086
[VERTICES]
;;Link X-Coord Y-Coord
;;-------------- ------------------ ------------------
**********************************************************
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**********************************************************
**********************************************************
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**********************************************************
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**********************************************************
------------------------------
Date: Thu, 26 Nov 2009 17:48:42 +0100
From: Maurizio Cingi <mrz...@GMAIL.COM>
Subject: Re: orifice in SWMM5
Hi Robert,
thank you for your kind reply.
Just a few comments:
about 2nd - the continuity error decrease with a longer run (as %) but it is
only an "error dilution". Observing data you can see that the error (during
first ten minutes) is the same, then, when storage is full, it stops but the
total volume increases (due to overflow) so error % is less.....
attacched file -> graphic with Storage O2 volume and volume calculated as
integration of Q*dt
5th flow throught orefice is near correct (average value on more than few
time steps) but awfully unstable. I know that it can be viewed as a mere
aestethic problem but it is a strange behavior compared to the weir
stability in the same condition.
attacched file -> graphic with flow throught orifice (from swmm at time step
and average on 20 seconds
7th I recognize my example is an atipical model: at the beginning it was a
tipical model, then I purged it to eliminate every unnecessary
device/detail.
MC
2009/11/26 Robert Dickinson <Robert.E....@us.mwhglobal.com>
> Hi Maurizio,
>
>
>
> 1st Thank you for a very interesting example file,
>
> 2nd You can eliminate the continuity error at the downstream node of your
> oriice if you run the model for 1 hour instead of 10 minutes,
>
> 3rd The equations for orifice flow and weir flow are different and the weir
> switches to an orifice flow equation when the depth is above the crown of
> the weir or the weir is surcharged. In effect in your model you are
> comparing a larger orifice for the surcharged weir and a smaller orifice for
> the surcharged orifice.
>
> 4th If you plot the weir and orifice flow together on a one run you can see
> the effect of the smaller orifice - the flow is delayed by 15 minutes.
>
> 5th If you use the SWMM 5 Statistics Tool on the Weir and Orifice for any
> length run you will see that the total flow through the Weir and Orifice
> have the same volume.
>
> 6th We should still investigate however, why a shorter model run shows an
> apparent continuity error at the downstream storage node, and finally
>
> 7th You model is atypical because it does not have any active outfalls but
> only ending storage nodes.
>
>
>
> I hope this helps.
>
>
>
> Robert E Dickinson
>
> SW/WW Technical Engineering Specialist
>
> MWH Soft, Inc
>
> 9340 Pontiac Drive Tel: 813-712-0664
>
> Tampa, Florida, 33626 Alt: 813-494-2919
>
> USA
>
> robert.d...@mwhsoft.com
>
> www.mwhsoft.com
>
>
>
> -----Original Message-----
> From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf Of
> Maurizio Cingi
> Sent: Thursday, November 26, 2009 5:49 AM
> To: SWMM-...@listserv.uoguelph.ca
> Subject: [SWMM-USERS] orifice in SWMM5
>
>
>
> I've found a problem using orifices in SWMM5 (5.0.018) .
>
> In the attacched model you can see that the orice flow becomes unstable
> when
>
> water height on both sides is between top and bottom of the orifice.
>
> Then, when the orifice is completely submerged, the flow is stable at 0.5
>
> cms (the correct value).
>
> With a weir instead of orefice there isn't any problem.
>
> Another problem: the volume in storage 02 increases less than the
>
> OrificeFlow*timestep ( Q* dt ) and generates a big (huge) continuity
> error.
>
>
>
> Best regards
>
> M.Cingi
>
>
> ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
>
>
>
> orifice_BUG.inp
>
> [TITLE]
>
>
>
> [OPTIONS]
>
> FLOW_UNITS CMS
>
> INFILTRATION HORTON
>
> FLOW_ROUTING DYNWAVE
>
> START_DATE 11/25/2009
>
> START_TIME 00:00:00
>
> REPORT_START_DATE 11/25/2009
>
> REPORT_START_TIME 00:00:00
>
> END_DATE 11/25/2009
>
> END_TIME 00:10:00
>
> SWEEP_START 01/01
>
> SWEEP_END 12/31
>
> DRY_DAYS 0
>
> REPORT_STEP 00:00:01
>
> WET_STEP 00:05:00
>
> DRY_STEP 01:00:00
>
> ROUTING_STEP 0:00:01
>
> ALLOW_PONDING NO
>
> INERTIAL_DAMPING PARTIAL
>
> VARIABLE_STEP 0.75
>
> LENGTHENING_STEP 0
>
> MIN_SURFAREA 0
>
> NORMAL_FLOW_LIMITED BOTH
>
> SKIP_STEADY_STATE NO
>
> FORCE_MAIN_EQUATION H-W
>
> LINK_OFFSETS DEPTH
>
> MIN_SLOPE 0
>
>
>
> [EVAPORATION]
>
> ;;Type Parameters
>
> ;;---------- ----------
>
> CONSTANT 0.0
>
>
>
> [OUTFALLS]
>
> ;; Invert Outfall Stage/Table Tide
>
> ;;Name Elev. Type Time Series Gate
>
> ;;-------------- ---------- ---------- ---------------- ----
>
> 0 0 FREE NO
>
>
>
> [STORAGE]
>
> ;; Invert Max. Init. Storage
>
> Curve Ponded Evap.
>
> ;;Name Elev. Depth Depth Curve
>
> Params Area Frac. Infiltration Parameters
>
> ;;-------------- -------- -------- -------- ---------- -------- --------
>
> -------- -------- -------- -----------------------
>
> O1 0 5 0 FUNCTIONAL 50 0
>
> 0 0 0
>
> O2 0 5 0 FUNCTIONAL 50 0
>
> 0 0 0
>
> W1 0 5 0 FUNCTIONAL 50 0
>
> 0 0 0
>
> W2 0 5 0 FUNCTIONAL 50 0
>
> 0 0 0
>
>
>
> [ORIFICES]
>
> ;; Inlet Outlet Orifice Crest
>
> Disch. Flap Open/Close
>
> ;;Name Node Node Type Height
>
> Coeff. Gate Time
>
> ;;-------------- ---------------- ---------------- ------------ ----------
>
> ---------- ---- ----------
>
> ORIFICE O1 O2 SIDE .5
>
> 0.65 NO 0
>
>
>
> [WEIRS]
>
> ;; Inlet Outlet Weir Crest
>
> Disch. Flap End End
>
> ;;Name Node Node Type Height
>
> Coeff. Gate Con. Coeff.
>
> ;;-------------- ---------------- ---------------- ------------ ----------
>
> ---------- ---- -------- ----------
>
> WEIR W1 W2 TRANSVERSE 0.5
>
> 1.84 NO 0 0
>
>
>
> [XSECTIONS]
>
> ;;Link Shape Geom1 Geom2 Geom3
>
> Geom4 Barrels
>
> ;;-------------- ------------ ---------------- ---------- ----------
>
> ---------- ----------
>
> ORIFICE RECT_CLOSED 1 1 0 0
>
> WEIR RECT_OPEN 1 1 0
>
> 0
>
>
>
> [DWF]
>
> ;; Average Time
>
> ;;Node Parameter Value Patterns
>
> ;;-------------- ---------------- ---------- ----------
>
> O1 FLOW 1.0 "" ""
>
> W1 FLOW 1.0 "" ""
>
>
>
> [REPORT]
>
> INPUT NO
>
> CONTROLS NO
>
> SUBCATCHMENTS ALL
>
> NODES ALL
>
> LINKS ALL
>
>
>
> [TAGS]
>
>
>
> [MAP]
>
> DIMENSIONS 0.000 0.000 10000.000 10000.000
>
> Units None
>
>
>
> [COORDINATES]
>
> ;;Node X-Coord Y-Coord
>
> ;;-------------- ------------------ ------------------
>
> 0 5810.185 5586.420
>
> O1 964.506 5000.000
>
> O2 3973.765 4984.568
>
> W1 1010.802 5987.654
>
> W2 4050.926 6003.086
>
>
>
> [VERTICES]
>
> ;;Link X-Coord Y-Coord
>
> ;;-------------- ------------------ ------------------
>
>
>
> **********************************************************
>
> * To sign off, email to: list...@listserv.uoguelph.ca *
>
> * In the body of the message type: signoff swmm-users *
>
> **********************************************************
>
>
>
> **********************************************************
> * To sign off, email to: list...@listserv.uoguelph.ca *
> * In the body of the message type: signoff swmm-users *
> **********************************************************
>
**********************************************************
* To sign off, email to: list...@listserv.uoguelph.ca *
* In the body of the message type: signoff swmm-users *
**********************************************************
------------------------------
Date: Thu, 26 Nov 2009 11:55:11 -0500
From: Robert E Dickinson <robert.d...@GMAIL.COM>
Subject: Re: orifice in SWMM5
Hi Larry,
That is a fair criticism and you are right that running the model longer
drives down the continuity error because the overall inflow and final
storage increases. However, the fact that the example model does not have
an outfall and simply a storage node as the downstream boundary condition is
affecting the stability of the orifice. The equation for the orifice flow
when both ends of the orifice are submerged and there is not outlet from the
model would tend to be unstable.
Best and Kind Regards,
Robert Edgar Dickinson
On Thu, Nov 26, 2009 at 11:39 AM, Larry Bodnaruk <bodn...@ae.ca> wrote:
> Bob, I don't agree with your recommendation to run the model for one hour
> to make the continuity error disappear. This does not solve the problem or
> reduce the continuity error and only masks it - it is only smaller in
> proportion to the overall volume, which is obviously greater if you run the
> model longer but it still exists in absolute terms and is a symptom of the
> instability problem.
>
> .................................................................
> Larry Bodnaruk, P.Eng.
> Practice Leader - Water Resources
> Associated Engineering Alberta Ltd.
> 1000 Associated Engineering Plaza
> 10909 Jasper Avenue
> Edmonton, Alberta
> Canada
> T5J 5B9
> Phone (780) 451-7666 office or (780) 969-6348 direct
> Fax (780) 454-7698
>
>
> >>> Robert Dickinson <Robert.E....@US.MWHGLOBAL.COM> 11/26/2009 7:40
> AM >>>
> Hi Maurizio,
>
>
>
> 1st Thank you for a very interesting example file,
>
> 2nd You can eliminate the continuity error at the downstream node of your
> oriice if you run the model for 1 hour instead of 10 minutes,
>
> 3rd The equations for orifice flow and weir flow are different and the weir
> switches to an orifice flow equation when the depth is above the crown of
> the weir or the weir is surcharged. In effect in your model you are
> comparing a larger orifice for the surcharged weir and a smaller orifice for
> the surcharged orifice.
>
> 4th If you plot the weir and orifice flow together on a one run you can see
> the effect of the smaller orifice - the flow is delayed by 15 minutes.
>
> 5th If you use the SWMM 5 Statistics Tool on the Weir and Orifice for any
> length run you will see that the total flow through the Weir and Orifice
> have the same volume.
>
> 6th We should still investigate however, why a shorter model run shows an
> apparent continuity error at the downstream storage node, and finally
>
> 7th You model is atypical because it does not have any active outfalls but
> only ending storage nodes.
>
>
>
> I hope this helps.
>
>
>
> Robert E Dickinson
>
> SW/WW Technical Engineering Specialist
>
> MWH Soft, Inc
>
> 9340 Pontiac Drive Tel: 813-712-0664
>
> Tampa, Florida, 33626 Alt: 813-494-2919
>
> USA
>
> robert.d...@mwhsoft.com
>
> www.mwhsoft.com
>
>
>
> -----Original Message-----
> From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf Of
> Maurizio Cingi
> Sent: Thursday, November 26, 2009 5:49 AM
> To: SWMM-...@listserv.uoguelph.ca
> Subject: [SWMM-USERS] orifice in SWMM5
>
>
>
> I've found a problem using orifices in SWMM5 (5.0.018) .
>
> In the attacched model you can see that the orice flow becomes unstable
> when
>
> water height on both sides is between top and bottom of the orifice.
>
> Then, when the orifice is completely submerged, the flow is stable at 0.5
>
> cms (the correct value).
>
> With a weir instead of orefice there isn't any problem.
>
> Another problem: the volume in storage 02 increases less than the
>
> OrificeFlow*timestep ( Q* dt ) and generates a big (huge) continuity
> error.
>
>
>
> Best regards
>
> M.Cingi
>
>
> ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
>
>
>
> orifice_BUG.inp
>
> [TITLE]
>
>
>
> [OPTIONS]
>
> FLOW_UNITS CMS
>
> INFILTRATION HORTON
>
> FLOW_ROUTING DYNWAVE
>
> START_DATE 11/25/2009
>
> START_TIME 00:00:00
>
> REPORT_START_DATE 11/25/2009
>
> REPORT_START_TIME 00:00:00
>
> END_DATE 11/25/2009
>
> END_TIME 00:10:00
>
> SWEEP_START 01/01
>
> SWEEP_END 12/31
>
> DRY_DAYS 0
>
> REPORT_STEP 00:00:01
>
> WET_STEP 00:05:00
>
> DRY_STEP 01:00:00
>
> ROUTING_STEP 0:00:01
>
> ALLOW_PONDING NO
>
> INERTIAL_DAMPING PARTIAL
>
> VARIABLE_STEP 0.75
>
> LENGTHENING_STEP 0
>
> MIN_SURFAREA 0
>
> NORMAL_FLOW_LIMITED BOTH
>
> SKIP_STEADY_STATE NO
>
> FORCE_MAIN_EQUATION H-W
>
> LINK_OFFSETS DEPTH
>
> MIN_SLOPE 0
>
>
>
> [EVAPORATION]
>
> ;;Type Parameters
>
> ;;---------- ----------
>
> CONSTANT 0.0
>
>
>
> [OUTFALLS]
>
> ;; Invert Outfall Stage/Table Tide
>
> ;;Name Elev. Type Time Series Gate
>
> ;;-------------- ---------- ---------- ---------------- ----
>
> 0 0 FREE NO
>
>
>
> [STORAGE]
>
> ;; Invert Max. Init. Storage
>
> Curve Ponded Evap.
>
> ;;Name Elev. Depth Depth Curve
>
> Params Area Frac. Infiltration Parameters
>
> ;;-------------- -------- -------- -------- ---------- -------- --------
>
> -------- -------- -------- -----------------------
>
> O1 0 5 0 FUNCTIONAL 50 0
>
> 0 0 0
>
> O2 0 5 0 FUNCTIONAL 50 0
>
> 0 0 0
>
> W1 0 5 0 FUNCTIONAL 50 0
>
> 0 0 0
>
> W2 0 5 0 FUNCTIONAL 50 0
>
> 0 0 0
>
>
>
> [ORIFICES]
>
> ;; Inlet Outlet Orifice Crest
>
> Disch. Flap Open/Close
>
> ;;Name Node Node Type Height
>
> Coeff. Gate Time
>
> ;;-------------- ---------------- ---------------- ------------ ----------
>
> ---------- ---- ----------
>
> ORIFICE O1 O2 SIDE .5
>
> 0.65 NO 0
>
>
>
> [WEIRS]
>
> ;; Inlet Outlet Weir Crest
>
> Disch. Flap End End
>
> ;;Name Node Node Type Height
>
> Coeff. Gate Con. Coeff.
>
> ;;-------------- ---------------- ---------------- ------------ ----------
>
> ---------- ---- -------- ----------
>
> WEIR W1 W2 TRANSVERSE 0.5
>
> 1.84 NO 0 0
>
>
>
> [XSECTIONS]
>
> ;;Link Shape Geom1 Geom2 Geom3
>
> Geom4 Barrels
>
> ;;-------------- ------------ ---------------- ---------- ----------
>
> ---------- ----------
>
> ORIFICE RECT_CLOSED 1 1 0 0
>
> WEIR RECT_OPEN 1 1 0
>
> 0
>
>
>
> [DWF]
>
> ;; Average Time
>
> ;;Node Parameter Value Patterns
>
> ;;-------------- ---------------- ---------- ----------
>
> O1 FLOW 1.0 "" ""
>
> W1 FLOW 1.0 "" ""
>
>
>
> [REPORT]
>
> INPUT NO
>
> CONTROLS NO
>
> SUBCATCHMENTS ALL
>
> NODES ALL
>
> LINKS ALL
>
>
>
> [TAGS]
>
>
>
> [MAP]
>
> DIMENSIONS 0.000 0.000 10000.000 10000.000
>
> Units None
>
>
>
> [COORDINATES]
>
> ;;Node X-Coord Y-Coord
>
> ;;-------------- ------------------ ------------------
>
> 0 5810.185 5586.420
>
> O1 964.506 5000.000
>
> O2 3973.765 4984.568
>
> W1 1010.802 5987.654
>
> W2 4050.926 6003.086
>
>
>
> [VERTICES]
>
> ;;Link X-Coord Y-Coord
>
> ;;-------------- ------------------ ------------------
>
>
>
> **********************************************************
>
> * To sign off, email to: list...@listserv.uoguelph.ca *
>
> * In the body of the message type: signoff swmm-users *
>
> **********************************************************
>
>
>
> **********************************************************
> * To sign off, email to: list...@listserv.uoguelph.ca *
> * In the body of the message type: signoff swmm-users *
> **********************************************************
>
> **********************************************************
> * To sign off, email to: list...@listserv.uoguelph.ca *
> * In the body of the message type: signoff swmm-users *
> **********************************************************
>
**********************************************************
* To sign off, email to: list...@listserv.uoguelph.ca *
* In the body of the message type: signoff swmm-users *
**********************************************************
------------------------------
End of SWMM-USERS Digest - 25 Nov 2009 to 26 Nov 2009 (#2009-124)
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