Cannot preview mesh motion!

dvinh

Hi all, I'm modeling a 2D airfoil which is hamornically moving up and down. An UDF is written to apply the motion to the the airfoil. All the internal grid surrounding the airfoil are modeled as deform zone with Spring-based Smooth and Local Remeshing Update methods. Time step size is 0.003125. When I previewed the motion, it worked for about 2-3 time steps and then it came up with Non-positive volume exits. I have tried with many Spring-factor and Boundary relaxtion method but it doesn't work. I'm wondering that is the problem has been set up in the right way? So I hope you guys can give me some hints if you have the same problem or any experiences with this problem. I'm looking forward to hear from you guys soon. Thank you very much. Nguyen Duc Vinh