Sound source localization of flow around circular cylinder by a virtual microphone array technique

Sound source localization technology is used to study the noise mechanism generated by flow around a circular cylinder. Detached-eddy simulation is performed to compute the flow field and the far-field noise is calculated with the Ffowcs Williams and Hawkings acoustic analogy. At first the simulation method is validated with the flow around circular cylinder at Re=3900. The numerical results are compared with the experimental data by other researchers. The following case is to simulate the flow around circular cylinder at Re=46000. The acoustic result is found in good agreement with the experimental measurements. The acoustic analogy result is used as an input for the noise localization process. Microphone array technique is applied to investigate sound generated by flow around a circular cylinder with emphasis on sound generation mechanism. Two sound source localization methods are considered, including Delay-and-Sum beamforming algorithm and a high resolution beamforming method. The sound source is associated with the lift dipole at the vortex shedding frequency. The sound source is associated with the drag dipole at the double vortex shedding frequency. The sound source can also be shown at other frequency. With frequency increasing, the strength reduces and there are some other sidelobe sources.