[artemiss1984]

Hi.

I want to simulate a 2d channel (unsteady) flow in fluent using the dynamic mesh technique. The upper wall of channel is stationary and the lower wall is deforming in sinusoidal motion (function of x and t). The inlet and outlet B.C s are pressure inlet and pressure outlet, therefore flow is completely induced with the lower wall motion. I could prepare the proper udf which is complied without error in Fluent but I have negative volume in the domain after grid updating. I guess it is due to dynamic mesh model.
I am using the two dynamic mesh models: smoothing,re meshing for lower deforming wall.stationary condition for upper wall.

I am very great full if somebody can help me.

[yoossie]

Hi,

I have a similar problem with the dynamic mesh in Fluent. I am simulating a 2D engine, I have followed the Tutorial 12, but trying to adapt it to my real problem due to I have not the .msh or .cas of this tutorial. The problem that I have found is in the events, when I am trying to introduce them in my problem I see that they have defined some border conditions that I don't have in my problem, but the worst is that I don't know where are located exactly, so, if someone has any idea of how to do or has the file and can send me, I will be very pleased.

My problem, as I am seeing that I haven't say, is also that appears some warnings (in the mesh motion) about negative volume (so artemiss1984 it must be the dynamic mesh, I am pretty sure ) cells...

If it isn't this...Could be also the dymanic mesh zones? I have defined the movement of my valves, and of my pistons, also my interior as deforming, and my walls as stationary...but I don't know if they are well defined.

Thanks for your answers, and sorry artemiss1984 for using your topic for asking my problem, but I think that could be useful for both of us.