Shear stress and noise metric reduction using active vibration

Abstract

The effects of active vibrational surface on wall shear stress and noise metric have been researched by the computational fluid dynamics method. The skin-friction drag and noise metric can be decreased by the active surface control. A sinusoidal vibration was imposed on the surface of a plate and the vibrational position located on downstream of the plate leading edge. The turbulence boundary layer was fully developed at the vibrational position. The downstream skin-friction drag exhibited a strong dependence on the control parameters (oscillation frequency and amplitude). A reduction in the trailing edge noise was obtained by the increasing of vibrational frequency and the appropriate choosing of amplitude. The maximum reduction in local skin friction drag is 64.3%. The noise metric can be decreased by 37.9 dB. Comparing the near-wall flow structures with and without control, it can be found that the turbulent kinetic energy and characteristic turbulence length scale were changed by the control.