Journal

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

57

1

1533-385X

11/2/2018

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

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