Authors: Vikram Deshpande; Brijesh Eshpuniyani; Sanjeev Sanghi
Addresses: Department of Applied Mechanics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India ' Department of Mechanical Engineering, Indian Institute of Technology (BHU), Varanasi, UP, 221005, India ' Department of Applied Mechanics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India
Abstract: For an upward moving ramp, compression waves of progressively increasing strengths emanate from the ramp surface and eventually coalesce into an oblique shock. A lag in wall pressure build up relative to fixed ramp values is observed which depends on ramp angle and angular velocity in a direct fashion. For an oscillating ramp, wall pressure response to varying ramp angles displays a hysteretic behaviour. Compressive/expansive effects generated during the ramp's upward/downward motions persist after the ramp changes its direction. Lags are observed during both wall pressure build up and relaxation which exhibit a similar dependence to ramp angle and angular velocity as in case I. The effect of ramp motion on boundary layer (thinning/thickening during upward/downward motions) is explained on the basis of fluid inertia and is reflected in increasing/decreasing velocity gradients inside the boundary layer. This in turn affects wall skin friction and temperature distributions inside the boundary layer.
Keywords: supersonic flow; moving ramps; ramp angles; particle velocity upwinding scheme; PVUS; pressure hysteresis; compression waves; oblique shock; angular velocity; ramp motion; boundary layers; fluid inertia; velocity gradients; wall skin friction; temperature distribution; shock wave boundary layer interaction; SWBLI; non-stationary obstructions; wall pressure response.
Progress in Computational Fluid Dynamics, An International Journal, 2015 Vol.15 No.3, pp.144 - 156
Received: 08 May 2021
Accepted: 12 May 2021
Published online: 26 May 2015 *