Acoustic Waves Generated by Vortex Shedding

Author: Nomoto, Hideki

Year: 1980

Degree: Engineer's thesis

Advisor: Culick, Fred E. C.

Committee Member: Unknown, Unknown

Option: Aeronautics

DOI: 10.7907/ghk0-az55

Abstract

An internal flow self-sustained oscillation system, which consists of a two-dimensional duct and a pair of baffles inside, is investigated experimentally. This system produces a high amplitude pure tone when certain flow and geometrical conditions are satisfied. The frequency of this generated tone seems to be determined by the longitudinal acoustic modes of the duct, while the dependence of pure tone production on flow and geometrical conditions seems to be related to the interaction between vortex shedding and acoustic feed back mechanism.

Some features on self-sustained oscillation systems are reviewed briefly and Rossiter's idea on the cavity tone system is applied for interpretation of the mechanism of the pure tone production.

Flow visualization shows stable vortical structure of the flow between the baffles when a pure tone is produced.

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