Noise control of subsonic flow past open cavities based on porous floors

2020 ◽  
Vol 32 (12) ◽  
pp. 125101
Author(s):  
Bo Li ◽  
Chuang-Chao Ye ◽  
Zhen-Hua Wan ◽  
Nan-Sheng Liu ◽  
De-Jun Sun ◽  
...  
Keyword(s):  
Subsonic Flow ◽  
Noise Control ◽  
Flow Past ◽  
Open Cavities

Subsonic Flow Over Open Cavities: Part 1 — Analytical Models and Numerical Investigations

2016 ◽  
Author(s):  
Weidong Shao ◽  
Jun Li
Keyword(s):  
Boundary Layer ◽  
Mach Number ◽  
Shear Layer ◽  
Layer Thickness ◽  
Boundary Layer Thickness ◽  
Feedback Loop ◽  
Subsonic Flow ◽  
Free Stream ◽  
Open Cavities ◽  
Free Stream Mach Number

The aeroacoustical oscillation and acoustic field generated by subsonic flow grazing over open cavities has been investigated analytically and numerically. The tone generation mechanism is elucidated with an analytical model based on the coupling between shear layer instabilities and acoustic feedback loop. The near field turbulent flow is obtained using two-dimensional Large Eddy Simulation (LES). A special mesh is used to absorb propagating disturbances and prevent spurious numerical reflections. Comparisons with available experimental data demonstrate good agreement in both the frequency and amplitude of the aeroacoustical oscillation. The physical phenomenon of the noise generated by the feedback loop is discussed. The correlation analysis of primitive variables is also made to clarify the characteristics of wave propagation in space and time. The effects of free-stream Mach number and boundary layer thickness on pressure fluctuations within the cavity and the nature of the noise radiated to the far field are examined in detail. As free-stream Mach number increases velocity fluctuations and mass flux into the cavity increase, but the resonant Strouhal numbers slightly decrease. Both the resonant Strouhal numbers and sound pressure levels decrease with the increase of boundary layer thickness. Results indicate that the instability of the shear layer dominates both the frequency and amplitude of the aeroacoustical oscillation.

Transverse subsonic flow past a cylinder

1980 ◽  
Vol 15 (2) ◽  
pp. 303-306 ◽  
Author(s):  
V. M. Bozhkov ◽  
L. E. Vasil'ev ◽  
S. V. Zhigulev
Keyword(s):  
Subsonic Flow ◽  
Flow Past ◽  
Flow Past A Cylinder
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