We describe a computationally efficient simulation-driven design methodology for single-element airfoils at high-lift conditions. Direct optimization of an accurate but computationally expensive high-fidelity simulation model based on Reynolds-Averaged Navier-Stokes equations is replaced by iterative updating and re-optimization of a cheap surrogate. The surrogate model exploits a low-fidelity ...

In this study, the flow past a finite-length tapered cylinder is numerically investigated via finite-volume method with Reynolds numbers ranging from 50-250 and taper ratio l = 1.5. The corresponding lift drag coefficients, as well Strouhal are presented. factors related to discontinuity, through of 100 - 200, in coefficient, which wake structure cylinder, explained. Furthermore, influence on d...

Wepresentmeasurements of the dissipative turbulent drag on a vibrating grid in superfluid 4He over awide range of (low) frequencies. At high velocities, the dissipative drag is independent of frequency and is approximately the same as that measured in normal liquid 4He. We present measurements on a similar grid in superfluid 3He-B at low temperatures which shows an almost identical turbulent dr...

Previous laboratory measurements on drag of tandem rigid bodies moving in viscous incompressible fluids found that a following body experienced less drag than a leading one. Very recently a laboratory experiment [52] with deformable bodies (rubble threads) revealed just the opposite — the leading body had less drag than the following one. The Reynolds numbers in the experiment [52] were around ...

In this paper, 3D flow past a long tapered tower is examined. A tapered tower is described by the taper ratio. Tapered cylinders are a good description of many structures, like wind turbine tower e.t.c. Similar to the flow around cylinders, the Reynolds number is the important flow parameter, and the Strouhal number represents the shedding frequency. These flow patterns are difficult to predict...

A simple expression is derived of the componential contributions that different dynamical effects make to the frictional drag in turbulent channel, pipe and plane boundary layer flows. The local skin friction can be decomposed into four parts, i.e., laminar, turbulent, inhomogeneous and transient components, the second of which is a weighted integral of the Reynolds stress distribution. It is r...

The aim of this study was to compare the speed fluctuation and the drag force in young swimmers between genders. Twenty-three young pubertal swimmers (12 boys and 11 girls) volunteered as subjects. Speed fluctuation was measured using a kinematical mechanical method (i.e., speedo-meter) during a maximal 25-m front crawl bout. Active drag, active drag coefficient and power needed to overcome dra...

In this work, we focus on two-dimensional, incompressible viscous channel flow over an infinitely long cylinder and examine the effect of controlled rotational cylinder oscillation in reducing the drag exerted on the cylinder. Based on an analysis of the open-loop simulations, a control system is designed that automatically determines the frequency of cylinder oscillation, based on the Reynolds...

Prior studies of wall bounded turbulence control have utilized Direct Numerical Simulation (DNS) which has limited investigations to low Reynolds numbers where viscous effects may play an important role. The current paper utilizes Large Eddy Simulation (LES) with the dynamic subgrid-scale model to explore the influence of viscosity on one popular turbulence control strategy, opposition control,...

Experiments have been carried out to study the influence of direction incoming flow relative rotor plane on values drag coefficient a multi-blade layout with power elements in form rotating cylinders variable cross-section. It is shown that force multipath depends Reynolds number, and practically remains constant range numbers (16-50)· 10 4 .According results series experimental data, dependenc...