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-   -   Displacements with the morpher model (http://www.cfd-online.com/Forums/star-ccm/74507-displacements-morpher-model.html)

Actone-Zero April 1, 2010 20:54

Displacements with the morpher model
 
Hi all,

I have a problem with the displacements I want to impose on a wall boundary, using the morpher model. I simulate the flow over an hydrofoil and I want to take into account the deformations with a simple beam equations so basically the solution depend only of the loading computed by STAR.
It seems that the displacement value I impose is added to the solution at each time step, so it is relative to the mesh deformation of the previous time step. Does anyone know how to impose displacement relative to the initial mesh, or compute the new displacements according to the previous mesh?

Thank you in advance.

tgi April 28, 2010 12:27

Hi,

I'm supposing you had implemented the morphing due field functions. There is an array called $$Position and one called $$SavedCoord. Position gives you the coordinates of the face at your timestep. SavedCoord contains the coordinates of the startup.. so you can calculate the displacement in every face by:

[$$Position[0]-$$SavedCoord[0],
$$Position[1]-$$SavedCoord[1],
$$Position[2]-$$SavedCoord[2]]

At first you should switch "Restore Saved Coordinates" on in the node Solver->Morpher. From this on it is possible to compute the new displacement. You can also access these vectors by UserCoding.

hope that helps...


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