[FlorentC]

Hello,
I'm trying to run a transient calculation on Fluent v17 to study acoustics around an airfoil exposed to a free stream of Mach 0.5. This tutorial about acoustics around a cylinder advises to use LES turbulence model with Smagorinsky-Lilly option along with Fluent's PRESTO! discretization for pressure, and 'fractional step' scheme for pressure-velocity coupling. These settings make my calculation diverge and I can't find a solution. I expect PRESTO! and LES settings to provide me better results than respectively second order discretization and laminar settings so I would like to have the calculation converging with these.

Calculation is pressure-based, air is ideal gas, airfoil is a no slip wall, the mesh is o-grid with a far-field pressure condition, time-step size is 1e-4s but going down 1e-6s doesn't make it either. The calculation is initialized using steady-state data obtained with second order and laminar settings.

The fact that my case is compressible when the tutorial is incompressible may play a role too.