Flow-induced vibrations of an elastic cylindrical shell conveying a compressible fluid

Abstract

The paper addresses the effects of generation and transmission of the vibro-acoustic energy in an elastic cylindrical shell filled with water. The energy input is produced by velocity and pressure pulsations due to the presence of an obstacle in a flowing fluid. It is assumed that there is no back-reaction of the vibro-acoustic response on the driving turbulent field. The concept of modal Green's functions and modal boundary integral equations is introduced and the role of elastic deformations of a tube is highlighted in view of the energy re-distribution between the structural and the acoustical transmission paths. Another important aspect of the problem of ‘flow-induced sound generation’, which is addressed in this paper, is the treatment of a CFD pressure output for the modelling of vibro-acoustic field generation. For an elastic shell in heavy fluid loading conditions, it is indicated that only the pressure distribution at the surface of a shell provided by a CFD solver is requested in order to adequately predict its coupled vibro-acoustic response. The ‘inner’ and ‘outer’ acousto-elastic domains are introduced and the low-order system of linear algebraic equations is set up, which is constituted by modal boundary equations and continuity conditions. Several ‘generic’ excitation cases are studied and the results of analysis are explained.