INFLUENCE OF LOW MACH NUMBER SHEAR FLOW ON ACOUSTIC PROPAGATION IN DUCTS

✍ Scribed by V PAGNEUX; B FROELICH

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 407 KB
• Volume: 246
• Category: Article
• ISSN: 0022-460X
• DOI: 10.1006/jsvi.2001.3572

✦ Synopsis

An experimental and theoretical investigation of the in#uence of a parallel shear #ow on the sound propagation in a circular duct is described. The theoretical model is based on a perturbation expansion at low Mach number of the modal equation for parallel shear #ows (Pridmore-Brown equation). In this model one assumes a rigid wall and no viscous or thermal e!ects. The experimental study was performed at low Mach number (M(0)05) with two propagating acoustic modes, and the Reynolds number range (0(Re(8500) allowed various pro"les for the mean #ow. Measurement of the pressure gave the behaviour of the axial wavenumber of modes 0 and 1 that were propagating in our experiment. A good agreement between experimental and theoretical results was obtained.

2001 Academic Press

having boundary condition *p/*r"0 for r"R, where u and v are the axial and radial components of acoustics velocity, p is the acoustic pressure, the acoustic density and the mean density. By assuming adiabatic conditions, the relation between and p (equation of state) is D Dt