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-   -   Mesh stifness devided by zero (https://www.cfd-online.com/Forums/cfx/254559-mesh-stifness-devided-zero.html)

maba February 18, 2024 03:13

Mesh stifness devided by zero
 
Hello everyone,
I am simulating a heaving plate using dynamic mesh. As the amplitude of oscillation is high, I wanted to use varying stiffness (1 [m^3 s^-1]/Wall Distance) to preserve the mesh near the wall where the mesh is fine. However, when the run starts, it gives the following error:






"PROBLEM ENCOUNTERED WHEN EXECUTING CFX EXPRESSION LANGUAGE
|
| The CFX expression language was evaluating:
| Mesh Stiffness
|
| The problem was:
| DIVIDE-BY-ZERO
|


Does anyone know what the problem is?

Gert-Jan February 18, 2024 07:53

The message shows that CFX is dividing by zero. So, somewhere the variable Wall Distance equals 0. Quite obvious, not?

You could prevent the division by zero by maximizing the denominator like: 1 [m^3 s^-1]/max(1e-6[m],Wall Distance)

Then CFX won't divide by 0, but by 1e-6[m] if Wall Distance is smaller than 1e-6. Not sure if 1e-6 is okay for your application. That is what you should test.


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