Aerodynamic and aero noise of stationary tire

The characteristics of aerodynamic and aero noise of stationary tire are investigated using computational fluid dynamics (CFD) and wind tunnel tests. A positive lift coefficient of almost 0.27 was found at all tested Reynolds numbers, while the drag coefficient was twice as large. The averaged pressure coefficient computed agrees with the measured, while the separation point predicted by numerical simulation is brought forward. The aero-noise numerical results using hybrid method based on large eddy simulation (LES) and FW-H formulations compares well with results from the wind tunnel test for total sound pressure level and noise spectra. Due to the defects of turbulence model and limited computer resources, the agreement of noise spectra for some test points in the frequency above 600 Hz is not the best. Sound energy of sound source and sound energy radiated from sound source are nearly proportional to the fourth power and sixth power of wind speed, respectively. At the simulated speeds, about 2.7% of sound energy comes from quadrupole sources, while 97.3% of sound energy comes from the dipole sources, which is the first time a quantitative description has been given. It should be pointed out that due to the different phases of dipole and quadrupole, the contribution of quadrupole to radiation is different at the receivers.