DOI: 10.1615/TSFP7
DEVELOPMENT OF WAKE VORTICES AND THE ASSOCIATED SOUND RADIATION IN THE FLOW PAST A RECTANGULAR CYLINDER OF VARIOUS ASPECT RATIOS
Краткое описание
Development of wake vortices and the associated sound radiation from a rectangular cylinder with various aspect ratios AR is studied by direct numerical simulations at Reynolds number 150 and Mach number 0.3. Both the lift and drag fluctuations operate as dipole sources from which acoustic waves are radiated in the lift and drag directions, respectively. The lift-dipole becomes the strongest at AR = 0.5 where the Strouhal number of vortex shedding takes a maximum. On the other hand, the magnitude of drag dipole becomes pronounced for AR ≤ 1 and increases with decreasing AR. The sound generated by the drag dipole is observed only in the upstream region. It is also found that for the smaller aspect ratios less than AR = 0.5, the primary wake vortices soom alignes in two row, which forms the absolutely unstable region in the dounstream region, leading to formation of secondary vortex street far downstream.