Control of Flow-Induced Noise Behind a Circular Cylinder Using Splitter Plates

Laminar vortex sheddings behind a circular cylinder with and without splitter plates attached to the cylinder base at the Reynolds numbers of 100 and 160 are simulated by solving the unsteady two-dimensional incompressible Navier-Stokes equations. The Strouhal number, lift, and drag rapidly change with the length of the splitter plate. Acoustic source functions are obtained from the computed near-field velocity and pressure using the Curie's solution of the Lighthill acoustic analogy. In the case of no splitter plate, the volume quadrupole noise is small at a low Mach number, compared with the surface dipole noise from the cylinder. When a splitter plate is attached to the cylinder, there are significant modifications of the dipole and quadrupole sources. Changes in the noise sources at Re = 100 are very different from those at Re = 160, and their differences are closely related to the secondary vortex generated at the tip of the splitter plate, Scattering effects at the edge of the splitter plate are also considered.