A Study on the Hartmann-Sprenger Tube Flow Driven by a Sonic Jet

Abstract

The Hartmann-Sprenger (H-S) tube flow driven by an underexpanded sonic jet is computed by solving the axisymmetric Euler equations using a Total Variation Diminishing (TVD) scheme, and its results are compared with the experiment. The compressible now causes resonance in the tube, resulting in violent fluctuation of the flowfield. In the experiment, shadowgraphs offer detailed now structure of the unsteady jet in the open space between the nozzle and the HS tube at the instant photograph is taken. The computational results, in contrast, have yielded sufficient information for the interactive fluctuating now in the whole impinging jet and H-S tube combined flow system. Physically the pulsating now in the H-S tube consists of four distinct phases: intake phase, transition to the expulsion, expulsion phase, and transition to the intake. It is expounded in this paper how the shock waves and expansion waves are generated in the H-S tube and interact with the impinging jet after escaping the tube, through the four phases of a cycle. Good agreement with the experiment has been obtained by the present inviscid Euler equations regarding the various fluctuating discontinuities in the open space.