[hubbens]

Dear all,

I am generating a 2D T-Rex mesh around a bobsleigh in Pointwise. However, the wake is not dense enough for viscous calculations due to the unsteady region behind the bluff body.

On the forum I found that local refinement is usually done by creating a separate region with a denser grid. Since the trailing part of the geometry is complex it is difficult to create such a region that closely follows the geometry outside the boundary layer.

Is there a possibility to have local grid refinement in a wake by for example inserting a source or a pole connector? Or are there other features to solve the problem?

Thanks in advance!
Harm

[dgarlisch]

It would be helpful if you attached a PW file or an image.

Based on your description...

You would need to do as you suggested. Create a region (domain) "just behind" where the sled's trex layers stop. This domain does not need to be connected to the sled itself. Set the connector spacing on this domain to the resolution you need. The mesh solver will fill in the gap between the sled's final trex layer and the refinement domain.

See this 3D example for what you can do in 2D.

[hubbens]

Thank you very much for your answer!

Do I have to create the region on the t-rex edge manually or can this be done automatically as well? I have included a snapshot of the region behind the athletes in the attachment and as you can see the region is highly curved so it would be much easier if this can be done automatically.

Looking forward to your reply.

[dgarlisch]

I have attached a picture of what I am trying to describe.

You dont need to modify any of the TRex edges. You just add an internal domain just outside the trex layers. This will be a 2-step process.

1. Build the grid without refinement region to find where the TRex layers stop. You have already done this.
2. Create a "hole" in the grid just behind the TRex layers by adding a new edge. Fill the hole with a new domain that has the finer spacing you need to capture the wake.

Use Edit, Add/Remove Edges... to add the hole.

DISCLAIMER:
I am not an expert at grid generation. I am hoping someone with more experience can chime in here and confirm or shoot-down my suggestions.