[william.z]

Hi guys,

I have have a problem with ZeroGap Overset Meshing in star ccm+. The case is not difficult. I just want to simulate a rotating tyre that is touching the ground. Therefore the tyre shape is cutted by the floor surface of the background region in order to obtain the contact patch (see fig.1). in order to perform the overset mesh, I included the tyre in a bigger cilynder that is my overset region and excides the background too. I decided to operate than the zerogap overset meshing, because of the fact that part of the overset mesh is outside the background. (see fig.2).
The zerogap wall, in which the overset gets on contact with the background is correctly found. but despite that the simulation gives the folowing error before starting the first iteration:

Some acceptorsCells are outside of background.
This might be due to an overlapping of overset regions or due to invalid mesh configuration!

[ping]

you need to take a close look at your mesh before and after you initialise the interface with one or more section planes through the mesh so you can see the two mesh.
then you place the section planes in a scalar displayer and look at the overset mesh field functions to see where your various overset cell types are as explained in this help topic Simulating Physics > Using Overset Meshes > Troubleshooting Overset Mesh.
and do you really need overset mesh anyway since some auto companies simplify things by putting a flat on the tyre then use a rotating reference frame to apply tangential velocity to the whole tyre wall boundary.