Investigation of Stabilization Effects in Hartmann-Sprenger Tubes

Abstract

An experimental investigation has been conducted in order to evaluate whether it is possible to reduce the sensitivity of the heating effect observed in Hartmann-Sprenger Tubes by applying swirl to the nozzle flow. A reference configuration derived from literature is compared against modified cavities incorporating stems of various lengths and a setup utilizing swirl. A stem of ≈50% cavity length has been found to have a moderate effect on operating mode stability and heating effects. Subjecting a cylindrical resonator to swirling flow has demonstrated to considerably increase the amplitude of the flow oscillations, leading to detrimental effects on heating rate due to increased mass transfer from cavity to environment. The swirl configuration therefore shows potential for improving resonators used for active flow control and Hartmann-Sprenger tubes designed for larger pressure amplitudes.