Distortion on the interface between solid and fluid

[Hfrossard]

Dear sirs,

I have been noticing that the mesh cannot handle a straight line or surface between solid and fluid without distorting it.

Please, refer to the images 01 and 02 that I am submiting. In the image 02, it should have a straight line on the limit between fluid and solid, instead it can be seen that the mesh is distorting this limit.

This distortion is probably giving me wrong results, once heat flux is strongly attached to the contact surface area. 

I imagine that if I keep refining the mesh, it would look better, but I do not want to do that to the whole problem. Instead, I just wanted to "fix" that the surfaces and edges should maintain the correct geometry.

Can anyone help me know if I can force the mesh to maintain the "straightness" of the limit between parts?

Best Regards!

[Jon.Wilde]

Hi,

Is this a flat plate or a curved surface?

[Hfrossard]

Hi,

Sorry, I forgot to mention. It is a curved surface.

Actually, it is a flow between two tubular surfaces, like in an extrusion Die Head.

[Jon.Wilde · Accepted solution]

OK, then that would explain how CFD is not producing a straight line. Your only real option is mesh refinement - we see this a lot and should still be producing good results.

If you are looking at heat transfer, also bear in mind you need at least two elements through any solid thickness.

Thanks,

Jon

[Hfrossard]

Dear Jon,

Thank you for the reply.

I am aware about elements count on the thickness.

Best Regards.

[Jon.Wilde]

Great, thanks for the update and for marking this as a solution, much appreciated! 🙂