All-theoretical prediction of cabin noise due to impingement of propeller vortices on a wing structureReported calculations of structure-borne cabin noise for a small twin engine aircraft powered by tractor propellers rely on the following three-stage methodological breakup of the problem: (1) the unsteady-aerodynamic prediction of wing lift harmonics caused by the whipping action of the vortex system trailed from each propeller; (2) the associated wing/fuselage structural response; (3) the cabin noise field for the computed wall vibration. The first part--the estimate of airloads--skirts a full-fledged aeroelastic situation by assuming the wing to be fixed in space while cancelling the downwash field of the cutting vortices. The model is based on an approximate high-frequency lifting-surface theory justified by the blade rate and flight Mach number of application. Its results drive a finite-element representation of the wing accounting for upper and lower skin surfaces, spars, ribs, and the presence of fuel. The fuselage, modeled as a frame-stiffened cylindrical shell, is bolted to the wing.
Document ID
19880032952
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Martinez, R. (Cambridge Acoustical Associates, Inc. Cambridge, MA, United States)
Cole, J. E., III (Cambridge Acoustical Associates, Inc. Cambridge, MA, United States)
Martini, K. (Cambridge Acoustical Associates, Inc. Cambridge, MA, United States)
Westagard, A. (Cambridge Acoustical Associates, Inc. MA, United States)