Simulation-Based Analysis of Flow-Generated Noise from Cylinders with Different Cross-Sections

Paper in proceedings, 2018

The flow-generated sound from cylinders with different cross-sections have been investigated using large-eddy simulation and an acoustic analogy. Three cylinders were investigated, with circular, square or elliptical cross-section respectively. The flow is in the sub-critical range and at low Mach number, and the source is acoustically compact. The flow around the cylinders exhibit significant differences, which are qualitatively investigated in detail. The vortex shedding frequency, the lift force fluctuations and the spanwise correlation, which are most important for noise generation, are computed for the three cases with large-eddy simulation. The resulting sound predictions are compared with aero-acoustic measurements and predictions of a semi-empirical model for the radiated sound. The semi-empirical model also provides a means for scaling of the sound results to other cylinder dimensions, flow speeds, and also for the transfer of results from air to water.