Viscous effects on the resonance of a slotted wind tunnel using finite elements

Abstract

Model flutter and oscillatory airload measurements will be affected by coupling with an acoustic vibration mode when the model frequency is near a tunnel resonance frequency. Widmayer, Clevenson, and Leadbetter conducted some experiments to measure the oscillatory aerodynamic forces and moments acting on a rectangular wing. The test results were in considerable error near the tunnel resonant frequency. Therefore, the authors want to predict the wind-tunnel resonant frequency accurately. The authors confine their concern to the wind tunnel that does not have a plenum chamber to simplify the problem, and they discuss the case in which the slot width is very small to consider viscosity effects.