Suppression of Cavity Flow Oscillations via Three-Dimensional Steady Blowing

Journal

Louis Cattafesta, Nishul Arora, and Yang Zhang

Yiyang Sun and Lawrence S. Ukeiley

2018

This paper presents an investigation of the flow physics and control of cavity flow oscillations using a three-dimensional (3-D) array of steady jets located near the cavity leading edge. The array injects 3-D, steady flow normal to the freestream to suppress the fluctuating surface pressure in a rectangular cavity with a length-to-depth ratio L/D of 6 for Mach 0.3 to 0.7. Sixteen configurations are assessed for their suppression as a function of the aggregate momentum coefficient Cμ, spatial duty cycle d, and dimensionless wavelength λ/D. Significant reductions of fluctuating surface pressure are observed. Schlieren and particle image velocimetry are performed to investigate the baseline and controlled flows. Companion large-eddy simulations with spanwise periodic boundary conditions at Mach 0.6 generally agree with the experiments, despite a significant difference in the Reynolds numbers. The simulations show that control reduces the pressure fluctuations inside the entire cavity, albeit at a higher level of Cμ. Spanwise wavelike structures produced by the control input distort the shear layer, inhibit the growth of large-scale vortical structures, and reduce the strength and length scale of turbulent fluctuations near the impingement region. A slot-configuration design guide is provided, which compares favorably with the limited available data in the literature. Read More: https://arc.aiaa.org/doi/abs/10.2514/1.J057012

AIAA Journal

1533-385X

10/31/2018

https://arc.aiaa.org/doi/abs/10.2514/1.J057012

https://doi.org/10.2514/1.J057012