The default least square interpolation method with overset meshes is susceptible to interpolation errors when the local donor-receptor stencil is not ideal locally to enhance solver robustness without sacrificing accuracy globally. This can potentially lead to reduced solver robustness. Often, in such situations, switching to the inverse distance interpolation method is sufficient to restore solver performance. However, the inverse distance interpolation is known to be less accurate than the default least-squares method, especially for gradients at the overset interface. Therefore, a hybrid interpolation method is introduced that selectively switches to the inverse distance method locally to enhance the robustness without sacrificing the accuracy. This method is recommended when the default interpolation method exhibits poor solver robustness and switching to inverse distance interpolation results in reduced solution accuracy.

To enable the hybrid method, first enable beta features (as described in Introduction) then use the following command:

solve/set/overset/interpolation-method

Select option 2 for hybrid interpolation.