Flow and Aeroacoustic Simulations for a Cylinder Using Lattice Boltzmann and Acoustic Analogy Methods

Flow and aero-acoustic simulations for a cylinder at different Reynolds number are performed using lattice Boltzmann and acoustic analogy methods. In the sound source region, the two-dimensional flow over a cylinder is computed by direct numerical simulation(DNS) and large eddy simulation(LES) using lattice Boltzmann method. In order to verify the accuracy of the flow model, the simulation results are compared with experimental data and corresponding results from other's studies. Under the condition of far field assumption, several observation points are taken from the location of the sound source around the cylinder. For prediction of the radiated noise, a far-field noise solver based on the Curle equation is used. We can obtain the pressure fluctuation and noise spectrum of the observation points by putting the flow data into the noise solver. The results validate that the overall sound pressure level of the far-field observation points increases with the increase of Reynolds number; the noise radiation directivity of flow over a cylinder is similar to the radiation directivity of a dipole source. The Lattice Boltzmann and acoustic analogy methods has good performance in computational aeroacoustics.