High-order multioperator compact schemes for numerical simulation of unsteady subsonic airfoil flow

On the basis of high-order schemes, the viscous gas flow over the NACA2212 airfoil is numerically simulated at a free-stream Mach number of $0.3$ and Reynolds numbers ranging from $10^3$ to $10^7$. Flow regimes sequentially varying due to variations in the free-stream viscosity are considered. Vortex structures developing on the airfoil surface are investigated, and a physical interpretation of this phenomenon is given.