valve directed by pressure
 

Hello

I want to write an UDF who moves a valve in function of the pressure around it. But I don't know how to do it in function of the pressure applied or if I should write a pivoting link between the valve and the support and the pressure will move the valve directly.

Thanks for your advices or help.

There is no need to ask exactly the same question three times.

Edit: the two other threads have since been removed.

You could move the valve as a function of the pressure in the fluid by using the dynamic mesh (moving/deforming mesh model). Specifically, use the DEFINE_GRID_MOTION macro and displace the valve boundary nodes as a function of the local pressure (with the C_P macro). Take care to ensure a high mesh quality is conserved throughout your simulation; use deforming for small valve displacements and enable remeshing should your geometry change significantly.

Hello

thanks for your answer `e`. I am a beginner in the using of UDF so I searched how to use the DEFINE_GRID_MOTION macro with the C_P macro. Is it possible to have an example?

The UDF manual is a good place to start learning how to code user-defined functions as they describe what each function does and also provides examples. C_P is a flow variable macro which retrieves the local cell pressure (it's not specific to the dynamic mesh). The example in the manual for the grid motion describes the deflection of a cantilever beam (start with this example and then change the dependent variable to pressure).