Turbulent blood flow may contribute to a variety of pathophysiological effects. Because of its postulated importance, this study was undertaken to determine whether turbulent flow does in fact occur in the human body. In 15 persons (seven normal, seven aortic valvular disease, one prosthetic aortic valve), point velocity was measured in the ascending aorta with a hot-film anemometer probe. In o...

The application of the Immersed Boundary ~IB! method to simulate incompressible, turbulent flows around complex configurations is illustrated; the IB is based on the use of non-body conformal grids, and the effect of the presence of a body in the flow is accounted for by modifying the governing equations. Turbulence is modeled using standard Reynolds-Averaged Navier-Stokes models or the more so...

The contribution deals with a self-consistent description of time-mean turbulent lubricant flow, i.e. flow through a wedgeshaped gap confined by counter-sliding solid surfaces. The methods adopted are matched asymptotic expansions, where the slenderness or aspect ratio of the gap and the accordingly defined Reynolds number represent the perturbation parameters. As a remarkable finding, a load-b...

By considering the entrainment properties of the turbulent boundary layer, a new and simple form of auxiliary equation has been derived for the calculation of the form parameter H. Comparison with experimental results shows very fair agreement and it should be possible to apply the method in circumstances where normal forms of the auxiliary equation would fail. Further experiment or analysis of...

This paper reviews turbulent boundary-layer control strategies for skin-friction reduction of aerodynamic bodies. The focus is placed on the drag-reduction mechanisms by two flow control techniques-spanwise oscillation and spanwise travelling wave, which were demonstrated to give up to 45 per cent skin-friction reductions. We show that these techniques can be implemented by dielectric-barrier d...

We investigate the early stages of mass convection in a colloidal suspension at high solutal Rayleigh number Ras. From the time evolution of shadowgraph images and by assuming a diffusive growth of the boundary layers we obtain an indirect measurement of the concentration boundary layer thickness delta* at the onset of convection. We show that the dimensionless boundary layer thickness delta=de...

Here we describe the application of a multiple camera planar particle image velocimetry (PIV) measurement to achieve a large field of view (FOV) in a high Reynolds number turbulent boundary layer. Measurements are performed over a FOV of 0.8m × 0.5m (2.25δ × 1.4δ, where δ denotes the boundary layer thickness) in the streamwise and wall-normal directions respectively in a turbulent boundary laye...

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...

Proper orthogonal decomposition (POD) is applied to the direct numerical simulation (DNS) of a turbulent boundary layer performed by Wu & Moin (2010), and the resulting POD modes of various scales are examined. The modes include structures resembling those observed in instantaneous flow fields, such as large-scale motions of streamwise velocity with ramp-like wall-normal growth. Other modes cor...