Acoustic radiation from oscillating rigid bodies in mean compressible flow

The problem of acoustic radiation from two-dimensional oscillating rigid bodies in compressible mean flow is considered numerically. The acoustic perturbation field is calculated by solving the acoustic equations derived from the unsteady Euler equations by linearizing about a steady mean flow and by assuming a single frequency disturbance. A computational code is developed which is validated by computing the unsteady loads and acoustic radiation due to an oscillating circualr cylinder in compressible flow. Numerical results are compared with the exact analytical solution. Excellent agreement is obtained. The validated code is employed to compute the acoustic radiation from oscillating airfoils in compressible mean flow. Parametric studies are performed by varying the Mach number of the mean flow, the angle of attack and the geometry (thickness and camber) of the airfoil. Conclusions are drawn about the magnitude and phase of acoustic radiation for various Mach numbers, angles of attack, and airfoil geometries.