I'd like to solve a low Re flow (about Re=100k)over an airfoil. I tried to choose the ideal gas density model in order to use far field pressure-far-field boundary condition. I also tried different turbolence model but the solution diverged in few iterations or residuals grew without reaching convergence. How can I do?

Use incombressible ideal gas for density model. Select symmetry boundary condition for your upper and lower boundaries (if 2D). Velocity inlet should be your inlet bc Pressure outle should be your outlet bc

I defined a geometry that i splited the mesh of it into 2parts(structure & unstruc.).the near zone to wing is structure and the other one is unstructure.Between two zones, i defined interfaces.in fluent after defining B.C.,interfaces,...,check geometry i doesn't have any problem, but after intializing to start solution,Fluent shows me Warning and when i check the mesh,it fails and i'll have handedness problem(right-handedness & left-handedness) regard