Onset of Cavity Oscillation From Transverse to Longitudinal Mode in a Supersonic Flow

被引:4
|
作者
Pandian, S. [1 ]
Desikan, S. L. N. [2 ]
Niranjan, Sahoo [3 ]
机构
[1] Vikram Sarabhai Space Ctr, Thiruvananthapuram 695022, Kerala, India
[2] Vikram Sarabhai Space Ctr, Wind Tunnel Data Div, Thiruvananthapuram 695022, Kerala, India
[3] Indian Inst Technol Guwahati, Dept Mech Engn, Gauhati 781039, Assam, India
来源
JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME | 2020年 / 142卷 / 06期
关键词
MECHANISM; LAYER;
D O I
10.1115/1.4046369
中图分类号
TH [机械、仪表工业];
学科分类号
0802 ;
摘要
Experiments are carried out in supersonic flow past cavities (L/D = 1-3) to comprehend cavity oscillation from transverse to longitudinal mode. To characterize this, time-resolved schlieren images and unsteady pressure measurements are carried out. For L/D = 1, the cavity oscillation is in the transverse direction which is characterized by a single vortex along with low frequency oscillations. In the present studies, for the given length and depth, the L/D = 2 cavity shows both transverse and longitudinal mode of oscillations. This dual nature is ascertained through high-speed schlieren images and large rise in the fluctuating pressure. For L/D = 3, the cavity oscillation is in the longitudinal direction accompanied by low values of fluctuating pressure component and number of discrete modes/tones. Hence, it is believed that the transverse to longitudinal mode of cavity oscillation in the present studies occurs between L/D = 2 and 3. These cavities are driven by a thick shear layer where the vortex convection is found to be nonlinear. The comparison of dominant modes/tones with modified Rossiter and Handa relations indicates the necessity to develop a suitable model for transitional cavities. In-depth analyzes in terms of cross-correlation as well as wavelet transform divulge the basis that generates cavity modes/tones and mode switching phenomena, respectively.
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页数:10
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