Turbulent flow separation over a wall-mounted hump model and its control using plasma actuators were studied numerically and experimentally. The hump model chosen in this study was that used in a 2004 NASA Langley CFD validation workshop for turbulent separation control using synthetic jets. The numerical simulations solved the Reynoldsaveraged Navier-Stokes equations using Fluent. Different tu...

This article can be considered as an extension of the paper of Fukagata et al. Phys. Fluids 14, L73 2002 which derived an analytical expression for the constituent contributions to skin friction in a turbulent channel, pipe, and plane boundary layer flows. In this paper, we extend the theoretical analysis of Fukagata et al. formerly limited to canonical cases with two-dimensional mean flow to a...

For aerospace or hypersonic cruise vehicle the state of the boundary layer is of great importance because for turbulent boundary layers, the thermal loads and skin friction are higher than in laminar boundary layers. Therefore , knowledge of cooling features and laminar-turbulent transition is necessary for the design of the thermal protection system (TPS). Different strategies are used to redu...

Vibration is a manual technique used widely to assist with the removal of pulmonary secretions. Little is known about how vibration is applied or its effect on the respiratory system. The purpose of this study was to describe mechanical consequences of vibration on the chest wall of a normal subject and the effects of vibration on expiratory flow rates and volumes. The effects of vibration were...

In the present work we follow the breakdown of pairs of counter-rotating vortices (CVP) and the consequence formation of packets of hairpins in uniform shear flows. We employ a recent developed method which is capable of following (numerically) the evolution of finite-amplitude localized vortical disturbances embedded in shear flows. The solution is carried out using Lagrangian variables in Fou...

Consider a steady Stokes flow bounded by a flat wall to which a separatrix, not tangent to the wall, is attached at point S. If the wall is made to slowly oscillate periodically with small amplitude in a longitudinal direction, then the Poincare map associated with this perturbed flow has a fixed point on the wall near S with an invariant manifold. This result also holds for flows bounded by a ...

The interaction of an impinging oblique shock wave with angle 30° and a supersonic turbulent boundary layer at Ma?=2.9 Re? = 2400 over wavy-wall is investigated through direct numerical simulation compared the on flat-plate under same flow conditions. A sinusoidal amplitude to wavelength ratio 0.26 moves in streamwise direction uniformly distributed across spanwise direction. influences interac...

Turbulence control in the form of a streamwise travelling wave transverse wall motion was studied numerically by employing direct numerical simulations (DNS). Both total and phase averaging were utilised to examine statistical behaviour turbulence affected forcing, with focus on skin friction. Comparison results from pure temporal spatial forcing are conducted, compilation data is used explore ...