CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   CFX (http://www.cfd-online.com/Forums/cfx/)
-   -   Moving mesh (http://www.cfd-online.com/Forums/cfx/26717-moving-mesh.html)

Martijn November 24, 2008 10:11

Moving mesh
 
Hi,

I am trying to simulate a pressure relief valve in CFX 11.0. When the pressure rises at the inlet the valve opens to discharge excess fluid. The disk lift (opening) of the valve is than governed by the fluid forces.

The problem with the model I have right now is that the mesh gets bad at large disk lifts (opening). To solve this problem I would like to load a beforhand made mesh which is modelled with a greater disk lift and a finer mesh when the disk lift reases a pre-defined value. Is it possible to make a fortran script to load several meshes at the right time? I have seen how multiple meshes are loaded in tutorial 20 (where also a valve is moddeled), but it is not clear to me yet how I make the importing of the meshes opening dependant.

Thanks.

Glenn Horrocks November 25, 2008 00:47

Re: Moving mesh
 
Hi,

You can also stop the simulation, interpolate onto the new grid and restart.

There is much better support for this type of simulation in V12.

Glenn Horrocks

Martijn November 25, 2008 04:45

Re: Moving mesh
 
Thanks for our response!

The problem with manually stopping and restartng is that the opening of safetyvalves quite unstable is, so it would take several times stopping and restarting for a simulation for only a very short time period. That's why I want to automate this.

Can you tell me why this type of problem is easier to solve in CFX 12?

Thanks.

Martijn

Glenn Horrocks November 26, 2008 22:46

Re: Moving mesh
 
Hi,

You can script the stopping and starting. That makes it a bit more manageable.

In V12 there are a lot more options for mesh motion, remeshing and related stuff. Also there is multiple configuration def files, where a single def file contains a series of linked runs with physics changes, mesh changes or other things happening. Should be very useful for your stuff. Ask for a beta version from your CFX support office and give it a try.

Glenn Horrocks


All times are GMT -4. The time now is 22:13.