DIRECT SIMULATION OF SOUND EMITTED BY A RAPIDLY ROTATING ELLIPTIC CYLINDER BY THE FINITE DIFFERENCE LATTICE BOLTZMANN METHOD

Direct simulations of acoustic waves emitted from a rapidly rotating elliptic cylinder are performed by the finite difference lattice Boltzmann method with the arbitrary Lagrangian Eulerian formulation. We have made it clear that the sound is generated by the interaction between the shed vortex and the edge of the cylinder. It is shown that the acoustic pressure increases as the aspect ratio of the elliptic cylinder increases up to 3 but the sound pressure becomes almost constant for cylinders of higher aspect ratio. The dependence of the acoustic pressure on the Mach number of the moving edge and the flow Mach number is also shown.