ACOUSTIC PERFORMANCE OF HOSES - A PARAMETRIC STUDY

Modeling of wave propagation in hoses, unlike in rigid pipes or wavegu ides, introduces a coupling between the inside medium, the hose wall, and the outside medium, This alters the axial wave number and thence t he corresponding effective speed of sound inside the hose resulting in sound radiation into the outside medium, also called the breakout or shell noise, The existing literature on the subject is such that a hos e cannot be integrated into the,whole piping system made up of section s of hoses, pipes, and mufflers to predict the acoustical performance in terms of transmission loss (TL), The present paper seeks to fill th is gap, Three one-dimensional coupled wave equations are written to ac count for the presence of a yielding wall with a finite lumped transve rse impedance of the hose material, The resulting wave equation can re adily be reduced to a transfer matrix form using an effective wave num ber for a moving medium in a hose section, Incorporating the effect of fluid loading due to the outside medium also allows prediction of the transverse TL and the breakout noise, Axial TL and transverse TL have been combined into net TL needed by designers, Predictions of the axi al as well as transverse TL are shown to compare well with those of a rigorous 3-D analysis using only one-hundredth of the computation time , Finally, results of some parametric studies are reported for enginee rs involved in the acoustical design of hoses. (C) 1996 Institute of N oise Control Engineering.