Numerical Simulation of Unsteady Flow in Resonance Tube

Computational results are presented for the unsteady flow in a powered Hartmann resonance tube. The results were obtained using the WIND code for the two dimensional viscous flow in a five-block solution domain that includes the CD nozzle supplying the jet to the closed end tube within the ambient surrounding. The computed results are presented for the unsteady flow mechanisms involved in the resonance tube operation. These include the filling and emptying of the tube, which causes the lateral deflection of the jet and the changing shock structure in the under-expanded jet. The time history and Fourier transform of the flow pressure oscillations are also presented. The fundamental resonance frequency is compared to that computed from an approximate analytical formula.