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-   -   UDF Format 8th Order Poly Fit (http://www.cfd-online.com/Forums/fluent/44971-udf-format-8th-order-poly-fit.html)

Jason June 8, 2007 12:36

UDF Format 8th Order Poly Fit
 
I am writting a UDF to model the Womersly solution for a tube. I have fit 8th order polynomials to the Bessel functions. When I use my code in MatLab I obtain the correct answer. When I format it for the UDF applied at the inlet velocity b.c. I beleif the problem to be associated with my 8th order polynomial fit. After ploting the velocity points from both the Matlab version and from Fluent, they match very closely from r/R = 0 to r/R = .5 but after that are radicaly different. Is there anyway of dealing with these "higher frequencies"? I interpert it with no error messages. I can send you the UDF and the MatLab m.file if anyone is interested in helping. Thanks, Jason


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