The flow field associated with the passage of the turbulent spot in a 3–D duct with streamline divergence under zero pressure gradients was investigated and displayed as contour plots of the velocity perturbation in plan and elevation view of the spot. It suggests that, streamline divergence has no strong effect on the internal structure of the spot and eddies and their propagation in the downs...

A numerical study is performed to investigate nonlinear processes during internal wave generation by the oscillation of a background barotropic tide over a sloping bottom. The focus is on the near-critical case where the slope angle is equal to the natural internal wave propagation angle and, consequently, there is a resonant wave response that leads to an intense boundary flow. The resonant wa...

The work on this theme will comprise a boundary layer analysis in channel flow. Here we will be looking at both the laminar and turbulent case of incompressible flow within the presence of shear stress and vorticity. This study for both cases is a very important concept to understand for boundary layers in channel flows. To accomplish this study, we used the Finite Element Method and Finite Vol...

Direct numerical simulation (DNS) is used to study the effect of individual (hemispherical) and distributed roughness on supersonic flat plate boundary layers. In both cases, roughness generates a shear layer and counter–rotating pairs of unsteady streamwise vortices. The vortices perturb the shear layer, resulting in trains of hairpin vortices and a highly unsteady flow. Mach 3.37 flow past a ...

A method for generating three-dimensional, time-dependent turbulent inflow data for simulations of complex spatially developing boundary layers is described. The approach is to extract instantaneous planes of velocity data from an auxiliary simulation of a zero pressure gradient boundary layer. The auxiliary simulation is also spatially developing, but generates its own inflow conditions throug...

This paper reports on recent efforts with the ultimate goal to obtain a fully self-consistent picture of turbulent boundary layer separation. To this end, it is shown first how the classical theory of turbulent small-defect boundary layers can be generalised rigorously to boundary layers with a slightly larger, i.e. moderately large, velocity defect and, finally, to situations where the velocit...

The dynamics of transitional and turbulent boundary layers is explored via a hybrid vortex filament/finite volume simulation scheme in which vortical structures are identified without the constraints imposed by the traditional assumption that they are synonymous with rotational regions. Vortex furrows consisting of elongated, streamwise-oriented, raised perturbations to the wall vorticity layer...

A simplified version of the near-boundary eddy flux parameterization developed recently by Ferrari et al. has been implemented in the NCAR Community Climate System Model (CCSM3) ocean component for the surface boundary only. This scheme includes the effects of diabatic mesoscale fluxes within the surface layer. The experiments with the new parameterization show significant improvements compared...

The mechanics of inhomogeneous turbulence in and adjacent to interfacial layers bounding turbulent and non-turbulent regions are analysed. Different mechanisms are identified according to the straining by the turbulent eddies in relation to the strength of the mean shear adjacent to, or across, the interfacial layer. How the turbulence is initiated and the topology of the region of turbulence a...