Fluid-resonant oscillations in a cavity flow with a honeycomb stack

• Simulations and experiments on aeroacoustically driven thermoacoustic phenomena. • Three-dimensional interactions between cavity flow and honeycomb stack. • Contributions to aerodynamic noise suppression and energy harvesting. • Significant influence of stack position on cavity flow and heat pump behavior. To control and utilize aerodynamic sound energy through thermoacoustic effects, this study investigates the effects of a multi-channel stack on fluid-resonant oscillations in a cavity flow. Compressible flow simulations were conducted for a cavity containing a honeycomb stack with an incoming turbulent boundary layer, and the results were validated through wind tunnel experiments. The effects of the vertical position of the stack relative to the cavity depth on the self-sustained oscillations and heat-pumping effects were examined. The placement of the stack significantly affected the acoustic resonance within the cavity, with mode shifts observed in shear layer oscillations at specific stack positions. When the stack was positioned near the cavity bottom, an effective heat flow was induced through the stack due to thermoacoustic heat pumping, resulting in a temperature gradient between the stack ends. These findings demonstrate the possibility for controlling self-sustained oscillations in cavity flows using a honeycomb stack, highlighting energy conversion mechanisms between sound and heat.