Analysis of Sound Radiated by Axisymmetric Vortex Ring

Sound generation by a vortex ring collision

Sound Generated by a Pair of Axisymmetric Coaxial Vortex Rings

The time-dependent acoustic field generated by the mutual interaction of a pair of coaxial viscous vortex rings advecting along a common axis of symmetry is simulated using a two-step numerical procedure. In the first step, the flowfield is predicted by solving the incompressible Navier–Stokes equations. In the second step, Powell’s vortex sound theory is used to predict the far-field acoustic ...

Effects of a background axisymmetric potential flow on vortex ring pairing sound

Analysis of motor fan radiated sound and vibration waveform by automatic pattern recognition technique using “Mahalanobis distance”

In recent years, as the weight of IT equipment has been reduced, the demand for motor fans for cooling the interior of electronic equipment is on the rise. Sensory test technique by inspectors is the mainstream for quality inspection of motor fans in the field. This sensory test requires a lot of experience to accurately diagnose differences in subtle sounds (sound pressures) of the fans, and t...

Computation of Vortex Shedding and Radiated Sound for a Circular Cylinder

The Lighthill acoustic analogy approach combined with Reynolds-averaged Navier Stokes is used to predict the sound generated by unsteady viscous ow past a circular cylinder assuming a correlation length of ten cylinder diameters. The twodimensional unsteady ow eld is computed using two NavierStokes codes at a low Mach number over a range of Reynolds numbers from 100 to 5 million. Both laminar o...