Direct numerical simulation of transitional airfoil noise

Abstract

A compressible direct numerical simulation (DNS) is conducted of a cambered airfoil at 0◦ angle of attack that is embedded in a wind-tunnel flow at a Reynolds number of Re c = 150, 000, based on the chord length, and at a Mach number of M = 0.25. Under these flow conditions, a long laminar boundary layer region develops on the airfoil suction side that separates and reattaches close to the trailing edge. This produces a complex acoustic source field, with essentially a flapping shear layer interacting with the trailing edge. The acoustic field radiated under these conditions shows close resemblance with the noise field generated by the laminar instability noise mechanism. The DNS domain comp..