scholarly journals Base Pressure Fluctuations on Typical Missile Configuration in Presence of Base Cavity

2018 ◽  
Vol 55 (2) ◽  
pp. 335-345 ◽  
Author(s):  
N. S. Vikramaditya ◽  
M. Viji ◽  
S. B. Verma ◽  
Naveed Ali ◽  
D. N. Thakur
Keyword(s):  
Pressure Fluctuations ◽  
Base Pressure ◽  
Base Cavity

Mitigation of Antisymmetric Mode and Drag with Base Cavities

2021 ◽  
Author(s):  
Viji M ◽  
Srinivas Nistala Vikramaditya
Keyword(s):  
Cavity Length ◽  
Pressure Fluctuations ◽  
Substantial Reduction ◽  
Base Pressure ◽  
Antisymmetric Mode ◽  
Azimuthal Mode ◽  
Total Drag ◽  
Base Cavity ◽  
Mach Numbers ◽  
The Impact

Abstract Experiments were carried out to examine the impact of base cavities on the base pressure fluctuations and total drag of a cylindrical afterbody for freestream Mach numbers 0.6-1.5. Significant improvement in the base pressure and a substantial reduction in the afterbody drag was noticed in the presence of a base cavity at subsonic Mach numbers. However, on increasing the cavity length beyond a certain value its performance deteriorates. At supersonic Mach numbers their effectiveness drops drastically. Tones in the spectra can be classified into two types depending on the dominant azimuthal mode which is either 0 or 1 and are referred to as symmetric and an antisymmetric mode, respectively. Spectra at subsonic Mach numbers exhibit tones which are related either to mode 0 or 1. However, at supersonic Mach numbers only tones related to mode 0 exist. The base cavity either, effectively suppress the antisymmetric mode or modify it into a symmetric mode resulting in mitigation of the tones related to antisymmetric mode.

Influence of base cavity on base pressure at subsonic and supersonic Mach numbers

2019 ◽  
Author(s):  
J. N. Murugan ◽  
Kiran Chutkey ◽  
S. B. Verma
Keyword(s):  
Base Pressure ◽  
Base Cavity ◽  
Mach Numbers

Base Pressure Fluctuations

1961 ◽  
Vol 33 (1) ◽  
pp. 59-63 ◽  
Author(s):  
Kenneth McK. Eldred
Keyword(s):  
Pressure Fluctuations ◽  
Base Pressure

Characteristics of base pressure fluctuations of a typical missile configuration with a propulsive jet

2017 ◽  
Vol 71 ◽  
pp. 695-705 ◽  
Author(s):  
M. Viji ◽  
N.S. Vikramaditya ◽  
S.B. Verma ◽  
Naveed Ali ◽  
D.N. Thakur
Keyword(s):  
Pressure Fluctuations ◽  
Base Pressure ◽  
Propulsive Jet

Modes of Base Pressure Fluctuations: Shape, Nature, and Origin

AIAA Journal ◽  
2019 ◽  
Vol 57 (9) ◽  
pp. 3933-3942
Author(s):  
M. Viji ◽  
N. S. Vikramaditya
Keyword(s):  
Pressure Fluctuations ◽  
Base Pressure

Mach Number Effect on Symmetric and Antisymmetric Modes of Base Pressure Fluctuations

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
N. S. Vikramaditya ◽  
M. Viji
Keyword(s):  
Mach Number ◽  
Vortex Shedding ◽  
Pressure Fluctuations ◽  
Base Pressure ◽  
Antisymmetric Mode ◽  
Recirculation Bubble ◽  
Pressure Drops ◽  
Wide Range ◽  
Convective Motions ◽  
Mach Numbers

An experimental study aimed at evaluating the influence of Mach number on the base pressure fluctuations of a cylindrical afterbody was performed over a wide range of Mach numbers from subsonic to supersonic speeds. Time-averaged results indicate that the coefficient of base pressure drops with the increase in the freestream Mach number at subsonic speeds and increases at supersonic Mach numbers. The coefficient of root-mean-square of the pressure fluctuations follows a decreasing trend with the increase in the Mach number. Examination of the spectra reveals different mechanisms dominate the pressure fluctuations from the center to the periphery of the base as well as with the change in the Mach number. Analysis of the azimuthal coherence indicates that all the dominant tones in the spectra can be classified either into a symmetric or an antisymmetric mode at subsonic Mach numbers. However, at supersonic Mach numbers, all the dominant tones in the spectra are symmetric in nature. The results from the cross-correlation suggest that two possible mechanisms of recirculation bubble pulsing and convective motions/vortex shedding are driving the dynamics on the base at subsonic Mach numbers. However, at supersonic Mach numbers, only single mechanism of the recirculation bubble pulsing dominates. Moreover, it indicates that the symmetric mode is associated with the dynamics of the recirculation bubble and the antisymmetric mode is related to the convective motions/vortex shedding.

Time-Series Analysis of Supersonic Base-Pressure Fluctuations

AIAA Journal ◽  
2004 ◽  
Vol 42 (3) ◽  
pp. 605-613 ◽  
Author(s):  
Jonathan R. Janssen ◽  
J. Craig Dutton
Keyword(s):  
Time Series ◽  
Time Series Analysis ◽  
Pressure Fluctuations ◽  
Base Pressure ◽  
Series Analysis
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