The Response of Simple Panels to Turbulent Boundary Layer Excitation

Structure- and fluid-borne acoustic power sources induced by turbulent flow in 90° piping elbows

“…In this paper, the structural-acoustic response of an elbow due to internal turbulent flow is investigated. The analysis approach is based on random structural-acoustic analysis procedures developed and applied previously in the aerospace (Powell, 1958;Wilby, 1967;Jacobs et al, 1970), and nuclear (Au-Yang and Connelly, 1977) industries, and later improved and formalized into the CHAMP (Combined HydroAcoustic Modeling Programs) procedure at ARL/Penn State (Hambric et al, 2004(Hambric et al, , 2005. Computational fluid dynamics (CFD) analyses are used along with empirical formulas to estimate wall pressure cross-spectra which are applied to finite element (FE) and boundary element (BE) models of the piping and internal working fluid.…”

“…This is only true in lightly damped systems, with widely spaced modes, and with negligible fluid-loading Z(o). Early analysis approaches (Powell, 1958, Wilby, 1967, Jacobs et al, 1970Au-Yang and Connelly, 1977) assumed negligible modal cross-coupling, along with homogeneous applied pressure fields. All modal cross-coupling terms are considered in the approach described here, however, and inhomogenous pressure fields, like those within fluid-filled piping elbows, are accounted for properly.…”

Boundary Layer Pressure Fluctuations and Structural Response

“…The noise measurements were carried out in the 9 inch x 6 inch subsonic working section of the boundary layer wind tunnel at the University of Southampton. The general arrangement of the tunnel is shown in Figure 11, and the construction and operation of the tunnel have been described briefly in (12) and in detail in (1, 16). The microphone and supporting aerofoil were mounted on a 6 inch diameter plug which could be inserted in a series of measuring positions along the length of the tunnel working section.…”

“…In the investigation, two panels of rectangular planform were considered. The panels were similar to one of the specimens discussed in (12), and were mounted on 6-inch diameter plugs which could be placede several locations along the tunnel working section. The basic panel dimensions were 4.0 in.…”

Validation of Methods to Predict Vibration of a Panel in the Near Field of a Hot Supersonic Rocket Plume

“…Wilby [2] and Cockburn & Robertson [3] have shown that physics-based vibro-acoustic modeling methods require a more rigorous spectrum description of FPL loads -including cross spectrum analysis which describes the spatial correlation characteristics of the aeroacoustic loading. There is presently no industry standard method for measuring spatial correlation of aeroacoustic loads.…”