From wind tunnel test,we get a serial of fluctuating velocity courses along the vertical direction at the inlet in time domain ,these are random processes, and the sampling frequence is known. Could it be imposed such inlet velocity BC in Fluent6.0 through UDF? Thanks!

this can be done either through a transient profile file or by an UDF.

Thank you for your reply.I am learning UDF now,could you explain it more detail that how it is realized through UDF & transient profile?thanx.

Hi David,

The following is a sample profile file you van use :

((david transient 4 1) (t 0 5 10 15) (u 0 1 2 2 2) )

hope this helps you.

sri

Hi Sri,

Thanks. My data is very large, so I am trying to import the velocity histories into Fluent through UDF by file operation. I meet a new problem now:I doubt whether Fluent could simulate this random problem. Since as the random BC is introduced, the field variables should be random process after convergence.This is an unsteady problem,but it differs from the periodical one. If, how we know it has achieved convergence when using unsteady solver?And how to get the result data?

David.

Hi David,

Given a particular instant of time,the converged solution will be calculated from the boundary conditions at that time.Convergence of the solution within each timestep is important.You have to save the data files after every timestep,if you are interested and I feel this will also help you in getting some nice animations.

hope this answers u'r question!

Regards, sri