Linearized and non-linear acoustic/viscous splitting techniques for low Mach number flows

✍ Scribed by Mohammad Farshchi; Siamak K. Hannani; Mohammad Ebrahimi

• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: English
• Weight: 171 KB
• Volume: 42
• Category: Article
• ISSN: 0271-2091
• DOI: 10.1002/fld.572

✦ Synopsis

Abstract

Computation of the acoustic disturbances generated by unsteady low‐speed flow fields including vortices and shear layers is considered. The equations governing the generation and propagation of acoustic fluctuations are derived from a two‐step acoustic/viscous splitting technique. An optimized high order dispersion–relation–preserving scheme is used for the solution of the acoustic field. The acoustic field generated by a corotating vortex pair is obtained using the above technique. The computed sound field is compared with the existing analytic solution. Results are in good agreement with the analytic solution except near the centre of the vortices where the acoustic pressure becomes singular. The governing equations for acoustic fluctuations are then linearized and solved for the same model problem. The difference between non‐linear and linearized solutions falls below the numerical error of the simulation. However, a considerable saving in CPU time usage is achieved in solving the linearized equations. The results indicate that the linearized acoustic/viscous splitting technique for the simulation of acoustic fluctuations generation and propagation by low Mach number flow fields seems to be very promising for three‐dimensional problems involving complex geometries. Copyright © 2003 John Wiley & Sons, Ltd.