CFD Online Discussion Forums

CFD Online Discussion Forums (
-   CFX (
-   -   Prescribing a complex deforming boundary (

ColinS September 20, 2010 12:36

Prescribing a complex deforming boundary
Preface: I am an academic user and therefore do not have access to ANSYS Support. I have been through all of the tutorials and have scoured these forums for weeks looking for an answer, to no avail. I have little to no experience with CEL/CCL or Fortran.

I am trying to create a 2D, one-way FSI simulation that has a known boundary deformation which cannot be prescribed using a simple equation, such as in the ball valve tutorial. An example of the deformation is given below, where the initial state is 1 and it contracts to state 2.

The profiles come from experimental data and, as such, are defined by discrete points at each time step. I have polynomial fit equations at each. How would I go about defining the boundaries with these polynomials at each time step? I cannot find any applicable code or examples of this. The closest option I have found is to create a mesh for each time step and then use a junction box routine to import them, such as in the ball valve tutorial from CFX V11, but this is less than preferable. Alternative ideas? Defining the motion or location of each node is how I would like to approach this.

stumpy September 20, 2010 15:51

Search the doc for "3D profile". You can read in the data points into a series of User Functions, one for each timestep. Then you need to write a huge nested if() statement that is a function of "t", so only the appropriate profile gets returned at the appropriate timestep. For a large number of timesteps this may become impractical; in this case you can use Fortran to do the last part (but still read in the profiles into User Functions). The boundary x,y,z mesh locations then need to call this funciton, passing in "t" as an argument.
Academic customers get support from Ansys. Just go to the Ansys customer portal and request an account the same as everybody else.

ColinS September 20, 2010 16:21

Many thanks, stumpy. My advisor also just informed me that we get support like everyone else; I'm not certain what made me think otherwise.

ghorrocks September 20, 2010 18:41

Yes, academic customers do generally get support, but they are often last in the queue after commercial customers. If you are doing "serious" academic research with CFX you should consider getting a research license (at least that is what they call it here) which gives you full, timely access to support. Costs a few extra bucks but doing serious work on CFX without support is simply wasting your time.

All times are GMT -4. The time now is 21:24.