CFD Online Discussion Forums

CFD Online Discussion Forums (https://www.cfd-online.com/Forums/)
-   CFX (https://www.cfd-online.com/Forums/cfx/)
-   -   Speed sweep (https://www.cfd-online.com/Forums/cfx/25491-speed-sweep.html)

Gustaf March 18, 2008 19:57

Speed sweep
 
Let's say I want to run a number of identical simulations: the same mesh, same boundaries in all locations except the inlet velocity, which I'd like to sweep from some min speed to some max speed.

It seems to me right now to do this I have to write a batch script that generates CCL and mulitiple (very large!) .def files just to change that one parameter.

Shurley there must be a simpler way?

Thannk you, Gustaf

Steven March 19, 2008 05:29

Re: Speed sweep
 
As far as I know thats the way to do it :( I just did 66 different mesh and def files for my airfoil simulation. In your case though, as your just changing the boundary condition is it possible to run the simulation as transinet and have a velocity that is a function of time and then each time step would be a solution with a different velocity?

Might want to wait for other responses to see if thats a valid way to do it though!

Steve

Chebeba March 19, 2008 17:59

Re: Speed sweep
 
I must say that I would have thought this type of analysis was a really common "bread & butter" type thing. It seems strange to me that it does not have better UI support.

Interesting suggestion with the transient solution. I read through the docs on transient. It seems it would make the problem more complex, since the solver would actually try to take the previous steps into account when the flow speed is increased. It appears to me that this adds computational complexity compared to solving a set of discrete steady state cases.

UnderwaterAlex March 19, 2008 18:06

Re: Speed sweep
 
If you want to take advantage of all the bells and whistles Ansys has to offer, you can probably do this using Design Explorer in an automated fashion. I have not used this product myself, but my understanding is that it is for exactly this sort of situation. Check online for more info.

Best of luck,

-Alex

Jonathan March 20, 2008 02:06

Re: Speed sweep
 
DesignXplorer works with the mechanical FEA tools. Not with CFX.

UnderwaterAlex March 20, 2008 11:15

Re: Speed sweep
 
Really? I thought you could couple DX through workbench to run CFX simulations as well. In CFX Pre 11.0 SP1, if you right click on an expression, one of the options is "Use as DX Parameter." At the last Ansys Conference I went to (San Diego - April 2007) they discussed using DX for multiphysics/FSI as well. Of course, like I said, I haven't used it but my impression was you could utilize it in CFX through Workbench.

Sorry if I have misled.

-Alex


All times are GMT -4. The time now is 00:05.