Narrow-Band Noise Sources

Narrow-band acoustic sources, where the unsteady scales of interest are larger than turbulence, can be computed using RANS.  Examples of unsteady flows where AFT has performed noise predictions include: bluff-body shedding, von Karman vortex streets, separation and stall, moving or deflecting bodies, vortex or wake impingements, and driven cavities.  Acoustic signatures are obtained once the unsteady RANS pressures are available, and are generated as a post-processing function using Lighthill-Curle theory.   As long as the acoustic bandwidths of interest are attributable to features outside the turbulent scales, the approach accurately predicts experimental noise measurements. 

Click on a menu item at left to see examples of the flows where AFT has computed acoustic sources and/or radiated noise.