Thursday, August 29, 2013

FSI error with Ansys Fluent or CFX


If you're getting one of the following errors while performing a FSI ( Fluid structure interaction ) simulation using ansys
Fluent coupling error :
 +====================================================================+
 |                      System Coupling Exception                     |
 +====================================================================+
 | Origin            : Transient Structural (Solution)                |
 | Error Code        : 2                                              |
 | Error Description :                                                |
 |    One or more elements have become highly distorted.  Excessive   |
 |   distortion of elements is usually a symptom indicating the need  |
 |   for corrective action elsewhere.  Try ramping the load up        |
 |   instead of step applying the load (KBC,1).                       |
 +====================================================================+

CFX coupling error :
 +--------------------------------------------------------------------+
 | ERROR #001100279 has occurred in subroutine ErrAction.             |
 | Message:                                                           |
 | CFX encountered the error: Read.  Fatal error occurred when reque- |
 | sting Total Mesh Displacement for FSI.                             |
 |                                                                    |
 |                                                                    |
 |                                                                    |
 |                                                                    |
 +--------------------------------------------------------------------+

This may occur if your solid is largely deforming at the very first step under your fluid pressure.
Remember that fluent has an operation pressure, cfx has a reference pressure too. All pressures you define are relative to this reference pressure. So it may cause a pressure increase in your model and cause a huge displacement resulting the above error.
Another reason might be if you're defining velocity inlet in wrong pressure. For example consider a pipe with X axis. Now if you wrongly define the velocity inlet toward Y or Z instead of X axis, the reduction in velocity at wall locations will cause a high pressure increase and same story.

Mos

1 comment:

  1. Hi Mostafa,
    I am faiz i want to do FSI analysis of 250m RCC chimney with wind in ANSYS FLUENT i don't how to proceed for FSI. I have done CFD analysis in Fluent can i use these results in FSI.

    ReplyDelete