Anuga-user Digest, Vol 40, Issue 3
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Today's Topics:
1. Re: Anuga-user Digest, Vol 40, Issue 1 (rajesh tailor)
----------------------------------------------------------------------
Message: 1
Date: Wed, 19 Oct 2011 17:56:43 +0530
From: rajesh tailor <tailor....@gmail.com>
Subject: Re: [Anuga-user] Anuga-user Digest, Vol 40, Issue 1
To: anuga...@lists.sourceforge.net
Message-ID:
<CAA1D9o6EBaRnLkmGEymsQpxEPHPNtqyXLTbdyTVOccmU_6=9...@mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"
Hello All,
Previously I queried about anuga. Now I want to know that what
is the minimum system requirement to generate a fine mesh upto resolution of
50m. My domain area is about 1000km^2. I am using the machine which have
16GB memory, even thought it is not generating the mesh with 2000
resolution.
And how to convert sww file to avi or other video format.
Regards
Rajesh Tailor
On Wed, Oct 12, 2011 at 10:44 AM, rajesh tailor
<tailor....@gmail.com>wrote:
> Hi All,
> I wish to simulate dam break phenomena in the following scenario:
> I have the volume/quantum of water as my initial input. I am unable to
> determine the flow rate with which water will flow from dam.
> I am using Inflow function for the same which require rate, polygon, domain
> as required inputs. How to set the rate of water outflow when the volume of
> lake is given.
>
> regards
> Rajesh Tailor
>
> On Fri, Oct 7, 2011 at 10:20 AM, rajesh tailor <tailor....@gmail.com>wrote:
>
>> Thanks Gareth,
>> If u dont mind, I will disturb you again if i will have
>> more queries regarding it... or will find any difficulty in my work...
>> Thanks a lot....
>> regards
>> Rajesh Tailor
>>
>>
>> On Fri, Oct 7, 2011 at 5:34 AM, <anuga-use...@lists.sourceforge.net
>> > wrote:
>>
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>>>
>>>
>>> Today's Topics:
>>>
>>> 1. quries related to anuga (rajesh tailor)
>>> 2. Re: quries related to anuga [SEC=UNCLASSIFIED]
>>> (Gareth...@ga.gov.au)
>>>
>>>
>>> ----------------------------------------------------------------------
>>>
>>> Message: 1
>>> Date: Tue, 4 Oct 2011 11:04:54 +0530
>>> From: rajesh tailor <tailor....@gmail.com>
>>> Subject: [Anuga-user] quries related to anuga
>>> To: anuga...@lists.sourceforge.net
>>> Message-ID:
>>> <CAA1D9o4mYGbADBb9kQoKTkar5YsoR+s=
>>> VWsyBZMXb...@mail.gmail.com>
>>> Content-Type: text/plain; charset="iso-8859-1"
>>>
>>> Hi All,
>>> I am using anuga in my project for simulation.
>>> Can anyone help me regarding question i have....
>>>
>>> I am a programmer and dont know anything which is related to geography.
>>> I am using DEM data to generate mesh topography using
>>> create_domain_from_regions() function to create domain.
>>>
>>> 1. How to differentiate a particular region from domain like flood water
>>> source with a finite volume of water at starting time of simulation with
>>> a
>>> specified stage, village.
>>> 2. Speed of water is automatically set by ANUGA. Is ANUGA library
>>> considering atmospheric pressure, elevation of water source, gravity,
>>> volume
>>> of water discharge from lake and other physical quantities which can
>>> affect
>>> the speed.
>>> 3. How to release a specified amount of volume from a specified flood
>>> water
>>> source ?
>>> 4. What does it mean by inner polygon, interior regions, interior holes,
>>> file_function and use of these terms ?
>>> 5. How to get quantities such as depth at any particular point/polygon
>>> after
>>> simulation from .sww files ?
>>>
>>> I got maximum inundation location and elevation of that location using
>>> get_maximum_inundation_location() and get_maximum_inundation_elevation()
>>> functions.
>>>
>>> If i want to break a wall of dam, during simulation how can i do it. If i
>>> know the dimension (height, length, width) of that wall.
>>>
>>> regards
>>> rajesh tailor
>>> -------------- next part --------------
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>>>
>>> Message: 2
>>> Date: Fri, 7 Oct 2011 10:46:51 +1100
>>> From: <Gareth...@ga.gov.au>
>>> Subject: Re: [Anuga-user] quries related to anuga [SEC=UNCLASSIFIED]
>>> To: <tailor....@gmail.com>, <anuga...@lists.sourceforge.net>
>>> Message-ID:
>>> <60D02F9C526B7F48B2194...@EXCCR01.agso.gov.au>
>>> Content-Type: text/plain; charset="us-ascii"
>>>
>>> Hi Rajesh,
>>> Here are a few thoughts on your questions - note that there are many
>>> different ways to use ANUGA, and the suggestions below may not be the only
>>> (or best) way to do these things.
>>>
>>> 1. How to differentiate a particular region from domain like flood water
>>> source with a finite volume of water at starting time of simulation with a
>>> specified stage, village.
>>> See the answer to 3 below.
>>>
>>>
>>> 2. Speed of water is automatically set by ANUGA. Is ANUGA library
>>> considering atmospheric pressure, elevation of water source, gravity, volume
>>> of water discharge from lake and other physical quantities which can affect
>>> the speed.
>>>
>>> ANUGA is solving the shallow water equations [see the ANUGA manual for a
>>> description of the equations]. These are a very commonly used model of water
>>> flow, so you should be able to find quite a few references on the web.
>>> Basically, ANUGA assumes a constant atmospheric pressure throughout the
>>> modelled domain (although I believe some users have made adjustments for
>>> variable atmospheric pressure, which are still experimental). The shallow
>>> water equations automatically account for gravity / elevation of water
>>> source / water volume etc - they are actually approximations of the more
>>> general principles of 'conservation of mass' and 'conservation of momentum'
>>> for the fluid.
>>>
>>> 3. How to release a specified amount of volume from a specified flood
>>> water source ?
>>>
>>> There are several ways that might be appropriate depending on your
>>> problem. Here are some methods:
>>>
>>> a) You can impose a given initial water elevation over the particular
>>> region of your domain by appropriately defining the stage initial condition
>>> (see the 'Getting Started' part of the manual for examples of defining the
>>> initial stage). Then, this will evolve according to the shallow water
>>> equations, so will flow into other parts of your domain if the topography
>>> dictates this.
>>> b) You can impose a certain rate of 'rainfall' over a given area of the
>>> domain, see the function anuga.shallow_water.forcing.Rainfall. As above,
>>> this will then flow through the domain according to the shallow water
>>> equations.
>>> c) You can impose a certain rate of 'inflow' through a given
>>> cross-section, using the 'Inlet_operator' in
>>> 'anuga.structures.inlet_operator'.
>>> d) You can force a given momentum flux along the boundaries (e.g. by
>>> using a dirichlet boundary condition). There are a number of ways to do
>>> this, see the functions in
>>> 'abstract_2d_finite_volumes/generic_boundary_conditions.py' and in 'shallow
>>> water.boundaries'
>>>
>>> ... and there are probably other ways. To understand how to use these,
>>> look at the manual (chapters 4-5-6) and the code itself. Their
>>> appropriateness will depend on your particular simulation.
>>>
>>>
>>> 4. What does it mean by inner polygon, interior regions, interior holes,
>>> file_function and use of these terms ?
>>> In general, if you come across a term that you don't understand, there
>>> are 2 good approaches to finding it. 1) Do a 'find' in the user manual, to
>>> see if there is a discussion of the term. If that fails, try 2) Do a 'grep'
>>> in the code, assuming you have the source installed and have the 'grep'
>>> program (should be on most linux distributions, and can probably be
>>> installed on windows). For example, if my source tree is in
>>> /trunk/anuga_core/source, then if I open a terminal in that directory and
>>> then type 'grep -r "mysearchterm" ./*' (without the single quotes), then you
>>> can find wherever the term 'mysearchterm' is mentioned in the code. It may
>>> appear often - if so, look for where it is defined in the code (e.g. if you
>>> are searching for a function, then the term 'def' will appear where it is
>>> defined).
>>>
>>> 5. How to get quantities such as depth at any particular point/polygon
>>> after simulation from .sww files ?
>>>
>>> Here's one way - there are probably others:
>>>
>>> The sww files are actually netcdf files, which is a standard binary file
>>> format [ lots of info on the web about these]. I typically use a python
>>> library called Scientific.IO.NetCDF to read the sww files. These will give
>>> you stage (over time) and elevation (just at a single time, because it
>>> doesn't change), and you can then compute depth at a given time by
>>> subtracting these 2 quantities. Again you will probably have to google on
>>> how to read the netcdf files, but an example is:
>>>
>>> # Open ncdf connection
>>> fid=NetCDFFile('sww_filename_goes_here')
>>>
>>>
>>> # Read variables
>>> x=fid.variables['x']
>>> x=x.getValue()
>>> y=fid.variables['y']
>>> y=y.getValue()
>>>
>>> stage=fid.variables['stage']
>>> stage=stage.getValue()
>>>
>>> elev=fid.variables['elevation']
>>> elev=elev.getValue()
>>>
>>> xmom=fid.variables['xmomentum']
>>> xmom=xmom.getValue()
>>>
>>> ymom=fid.variables['ymomentum']
>>> ymom=ymom.getValue()
>>>
>>> time=fid.variables['time']
>>> time=time.getValue()
>>>
>>> vols=fid.variables['volumes']
>>> vols=vols.getValue()
>>>
>>>
>>> # Extract depth at the 10th output step.
>>> Depth10= stage[10,:] - elev
>>>
>>>
>>> So Depth10 will contain the depth values at the 10th output step, with
>>> coordinates corresponding to x & y. If you find the index of the coordinate
>>> you want in the x,y vectors (e.g. by calculating the distance of all points
>>> from the point you want and finding the index of the minimum), then you can
>>> extract the depth there.
>>>
>>>
>>> If i want to break a wall of dam, during simulation how can i do it. If i
>>> know the dimension (height, length, width) of that wall.
>>> If you want the dam to break at the very start of the simulation, then
>>> you can just define the initial stage as though the dam were present, but
>>> ignore the dam in the underlying topography - the shallow water equations
>>> will do the rest. This is typically what people do when computing idealised
>>> 'dam break' solutions to the shallow water equations.
>>>
>>> To actually have a dam for a time, and then remove it, would be more
>>> complex - I can't suggest an easy method. The idea would be to figure out
>>> how to redefine the topography mid-simulation (should be doable, but would
>>> probably require a good knowledge of the code).
>>>
>>> Hope this helps,
>>> Gareth.
>>>
>>>
>>>
>>> Gareth Davies
>>>
>>> Hydrodynamic Modeller
>>>
>>> Regional Risk Section,
>>>
>>> International Group
>>>
>>>
>>>
>>> Geoscience Australia.
>>>
>>> Ph: (02) 6249 9655
>>>
>>>
>>>
>>>
>>>
>>>
>>> From: rajesh tailor [mailto:tailor....@gmail.com]
>>> Sent: Tuesday, 4 October 2011 4:35 PM
>>> To: anuga...@lists.sourceforge.net
>>> Subject: [Anuga-user] quries related to anuga
>>> Hi All,
>>> I am using anuga in my project for simulation.
>>> Can anyone help me regarding question i have....
>>>
>>> I am a programmer and dont know anything which is related to geography.
>>> I am using DEM data to generate mesh topography using
>>> create_domain_from_regions() function to create domain.
>>>
>>> 1. How to differentiate a particular region from domain like flood water
>>> source with a finite volume of water at starting time of simulation with a
>>> specified stage, village.
>>> 2. Speed of water is automatically set by ANUGA. Is ANUGA library
>>> considering atmospheric pressure, elevation of water source, gravity, volume
>>> of water discharge from lake and other physical quantities which can affect
>>> the speed.
>>> 3. How to release a specified amount of volume from a specified flood
>>> water source ?
>>> 4. What does it mean by inner polygon, interior regions, interior holes,
>>> file_function and use of these terms ?
>>> 5. How to get quantities such as depth at any particular point/polygon
>>> after simulation from .sww files ?
>>>
>>> I got maximum inundation location and elevation of that location using
>>> get_maximum_inundation_location() and get_maximum_inundation_elevation()
>>> functions.
>>>
>>> If i want to break a wall of dam, during simulation how can i do it. If i
>>> know the dimension (height, length, width) of that wall.
>>>
>>> regards
>>> rajesh tailor
>>>
>>> -------------- next part --------------
>>> An HTML attachment was scrubbed...
>>>
>>> ------------------------------
>>>
>>>
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>>> threats, fraudulent activity, and more. Splunk takes this data and makes
>>> sense of it. IT sense. And common sense.
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>>>
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>>>
>>> End of Anuga-user Digest, Vol 40, Issue 1
>>> *****************************************
>>>
>>
>>
>
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