“…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.…”