Study of the Flow and Acoustic Fields in a Rigid-Walled Channel of Circular Cross-Section with a Local Axisymmetric Narrowing: A Theory

The analytical and numerical method is developed for solving the problems of noise generation by flows in channels with local geometrical inhomogeneities. The obtained fields of hydrodynamic parameters are used in this method to describe the noise sources, and the Green's function technique and eigenfunction method, as well as the methods of correlation and spectral analysis are applied to find the flow and acoustic fields. Based on the method developed, the problem of noise generation by a steady flow in an infinite straight rigid-walled channel of circular cross-section with local axisymmetric narrowing is solved, and analytical expressions for hydrodynamic and acoustic characteristics of the flow are obtained.