Passive control of cylinder aeolian tone by surface protrusions at low Reynolds number

Aerodynamic noise control is important for various engineering applications, including automobiles. To develop effective methods the flow and sound of bluff bodies, past a cylinder usually studied as simplified problem. In this study, passive technique using surface protrusions was developed to suppress aeolian tone generated by two-dimensional laminar circular cylinder. Protrusions were created on front rear surfaces an optimization approach based lattice Boltzmann adjoint methods, allowing complex geometries. The computational results revealed that pair could stabilize separated shear layers fixing separation points their tips, whereas can interfering with interaction between top bottom layers. Consequently, these shapes effectively suppressed vortex shedding while decreasing mean drag. A shape symmetrical reduced 3.6 dB.