TY - GEN

T1 - Computational analysis of the characteristics of subsonic, transonic and supersonic base flows

AU - Kawai, Soshi

AU - Fujii, Kozo

PY - 2005

Y1 - 2005

N2 - The physics of cylindrical base flows at subsonic to supersonic speeds are computationally investigated with LES/RANS hybrid methodology. When the free-stream Mach number increases from subsonic to supersonic speeds, time-averaged base pressure experiences three different phases; (1) base pressure decreases in proportion to dynamic pressure at the subsonic speeds with Mach numbers less than 0.8, (2) base pressure begins to fall rapidly as the free-stream Mach number approaches to sonic speed, (3) base pressure gradually decreases toward an asymptotic value at supersonic speeds. The position of the high-pressure region behind the base which strongly depends on the characteristics of freeshear layers at each speed range is one of the dominant factors that determine the base pressure. The dominant factor that determine the time-averaged characteristics of base flows changes from subsonic to supersonic speeds; unsteady vortices shedding from the instability of free shear layers at subsonic speeds, oscillations of front and rear local shock waves along the free shear layer at transonic speeds, and oscillations of the free shear layer and the recompression shock wave at supersonic speeds.

AB - The physics of cylindrical base flows at subsonic to supersonic speeds are computationally investigated with LES/RANS hybrid methodology. When the free-stream Mach number increases from subsonic to supersonic speeds, time-averaged base pressure experiences three different phases; (1) base pressure decreases in proportion to dynamic pressure at the subsonic speeds with Mach numbers less than 0.8, (2) base pressure begins to fall rapidly as the free-stream Mach number approaches to sonic speed, (3) base pressure gradually decreases toward an asymptotic value at supersonic speeds. The position of the high-pressure region behind the base which strongly depends on the characteristics of freeshear layers at each speed range is one of the dominant factors that determine the base pressure. The dominant factor that determine the time-averaged characteristics of base flows changes from subsonic to supersonic speeds; unsteady vortices shedding from the instability of free shear layers at subsonic speeds, oscillations of front and rear local shock waves along the free shear layer at transonic speeds, and oscillations of the free shear layer and the recompression shock wave at supersonic speeds.

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M3 - Conference contribution

AN - SCOPUS:84884970440

SN - 9781624100598

T3 - 35th AIAA Fluid Dynamics Conference and Exhibit

BT - 35th AIAA Fluid Dynamics Conference and Exhibit

T2 - 35th AIAA Fluid Dynamics Conference and Exhibit

Y2 - 6 June 2005 through 9 June 2005

ER -