Hi all,

I am using Fluent to move a 4m car over 100m in a straight line through an unstructured dynamic mesh. I am trying to maintain cell refinement close to the body, within about 10m, but Fluent keeps introducing huge cells.

I have varied every possible parameter and been through all the tutorials and still can't resolve this. Can anyone offer some practical advice?

Thanks, Shuto.

Is the only reason your mesh is unstructured because of the details of the car?

If so, then you could do a local volume around the car (probably an elogated cube), and mesh the outer surfaces with a mapped quad mesh. Then mesh the local volume with a tet/hybrid mesh, and mesh the rest of the model as a structured mesh. This way, instead of doing the spring meshes, you can do the dynamic layering on the structured mesh and move the entire hybrid mesh (instead of moving the faces of the car and doing a local remesh / spring-based smoothing of the entire volume). It would seem to me that if you set it up like this, you could have the dynamic layering in front of and behind the hybrid volume, and never have to deal with the other types of dynamic mesh.

Like I said before, I've never actually dealt with dynamic meshes before, but I've seen them used a lot, and it seems to me that this would work. If not... um... sorry about that!

Hope this helps, and goodluck Jason

Hi Jason,

Thanks for your input. The main reason I am trying to use an unstructured mesh is to enable more complex overtaking maneouvres once I have got the straight line working so I can make comparisons.

Ideally I'd like the overtaking vehicle to approach in the same lane, pull out, pass, and pull in again. Once I get more sophistication built in I'd like the vehicles to be accelerated and rotated by the aerodynamic forces. Maybe I am being over ambitious...

Thanks again! Shuto.