Fonction for stability analysis

[Franck Yahouamatiahoua]

Hello Guys!

Im trying to carry out stability analysis with Open VSP. I need to study Dynamic Stability and Static Sability.

Then i think i have to choose a "Stability type" ("Steady", "P Analysis", "Q Analysis" and "R Analysis") but i don't know which ones suit to my problems (Static Stability and Dynamic Stability). 

Could someone help me please?

Thanks!

[Rob McDonald]

Simply running 'Steady' mode will calculate all the steady stability derivatives.

Running P, Q, R Analysis will also do a sine-pulse in roll, pitch, and yaw to calculate unsteady derivatives.

For static analysis, plain Steady mode is plenty.

For dynamic analysis and greatest accuracy, you should also run P,Q,R.

Rob

--
You received this message because you are subscribed to the Google Groups "OpenVSP" group.
To unsubscribe from this group and stop receiving emails from it, send an email to openvsp+u...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/openvsp/42626fa6-d331-46e9-b1d5-6e66262b9cdan%40googlegroups.com.

[Franck Yahouamatiahoua]

Thanks Rob, that's clear :)

Franck

[Zack Seymour]

Hello,

I apologise if I'm being slow, but where in the stability file is information on the derivatives due to control surface deflections?

To clarify, what I mean is a non-dimensionalised version of (for example) d(CMx)/d(epsilon), which would be the change in rolling moment due to an aileron deflection. Clearly there are a few of these types of derivatives - are these included in the stability file?

Again, apologies if this has already been answered somewhere, although I have had a bit of a look prior to leaving this message.

Many thanks,

Zack

[Zack Seymour]

Actually scratch that - I didn't realise that for this to work it needs to use the VLM instead of panel solver. 

Please correct me if this is wrong, but I've personally been able to get the results I want using the VLM but not panel - hope this helps people in future!

Zack

[Rob McDonald]

You are correct.

This situation may change in the future, but for now surface deflections are only done in the thin surface mode.

Rob

[skyc...@gmail.com]

I'm getting an error using the steady analysis where it can't find a control surface.  How does it know what control surface groupings to use, and does it need to be explicit (ie the control group must only contain those controls which are on surfaces that are part of the geom set that you're running the analysis).  It also created an empty .stab file.  Wondering if it's because of the same issue.

Thanks!

Bryan