It is known that low-frequency components of three-dimensional vortical disturbances in the free stream can be entrained into the boundary layer due to the nonparallel flow effect, producing significant distortion in the form of alternate thickening and thinning of the layer in the spanwise direction. This observation goes back to Dryden (1936) and Taylor (1939) who, in fact, suggested that the...

Turbulence physics responsible for high skin-friction drag in turbulent boundary layers is first reviewed. A self-sustaining process of near-wall turbulence structures is then discussed from the perspective of controlling this process for the purpose of skin-friction drag reduction. After recognizing that key parts of this self-sustaining process are linear, a linear systems approach to boundar...

to enhance the understanding of the impact of obstacle buildings on pollution transportationand dispersion in the atmospheric boundary layer, it is necessary to know the atmospheric flow characteristics over terrains. wind flow characteristics in a boundary layer over a step-shaped cliff topography model with rough and smooth surfaces were studied numerically using computational fluid dynamics ...

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One-way coupled Euler-Lagrangian simulations of bubbles in a spatially evolving turbulent boundary layer were performed. The simulation parameters were chosen to match an experiment by Sanders et al. (2006), though the Reynolds number of the boundary layer was lower than experiment. The bubbles were observed to migrate away from the wall, as observed in experiment. Budgets of the forces on the ...

In this study, the influence of a geostrophically balanced horizontal density gradient on turbulent convection in the ocean is examined using numerical simulations and a theoretical scaling analysis. Starting with uniform horizontal and vertical buoyancy gradients, convection is driven by imposing a heat loss or a destabilizing wind stress at the upper boundary, and a turbulent layer soon devel...

Shock waves generated at different parts of vehicle interact with the boundary layer over the surface at high Mach flows. The adverse pressure gradient across strong shock wave causes the flow to separate and peak loads are generated at separation and reattachment points. The size of separation bubble in the shock boundary layer interaction flows depends on various parameters. Reynolds-averaged...

This Resource Letter provides a guide to the literature on fully developed turbulence in fluids. It is restricted to mechanically driven turbulence in an incompressible fluid described by the Navier-Stokes equations of hydrodynamics, and places greatest emphasis on fundamental physical questions. Journal articles and books are cited for the following topics: The Navier-Stokes equations, qualita...

The separation of a turbulent boundary layer, which is encountered in devices such as airfoils, diffusers and turbomachinery, is one of the most challenging research topics in fluid mechanics. Its understanding and its prediction with turbulence models are however still not satisfactory. The reason may be partly due to a shortage of reliable data from numerical simulations, which account for Re...