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Showing 1 to 13 of 13 for “"riblets"”.
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Riblets in the viscous sublayer : Optimal Shape Design of Microstructures
Previous research has established that a smooth surface has not necessarily minimal drag: Many experiments by different laboratories, e.g. NASA and DLR Berlin, indicate that an extra surface layer with tiny grooves aligned in the stream-wise direction can be used to reduce the drag. The aim of this …
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Geometry mediated drag reduction using riblets and wrinkled surface textures
… and reducing the viscous drag force, use of riblets have been banned in various competitions such as the America's Cup. The current thesis work is partly focused on theoretical and numerical modelling (using the open source CFD package OpenFOAM) of the evolution of viscous boundary layers in …
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Effects of riblets on the performance of the supersonic through-flow fan cascade blades
An experimental study to determine the effects of riblets on the performance of the supersonic through-flow fan (STF) cascade blades was performed. The two-dimensional cascade was tested in the Virginia Polytechnic Institute and State University intermittent wind tunnel facility, where the Mach and …
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Contribution à l'étude expérimentale sur la réduction des pertes de charge dans les tuyaux au moyen de "riblets"
… sur la technique qui utilise des « riblets ». Cette technique récente consiste à modifier la géométrie de la paroi à l'aide de micro-rainures dans le sens du courant appelées « riblets ». Le but de cette étude expérimentale est de déterminer l'effet réducteur de traînée des « riblets …
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Drag reduction using riblet film applied to airfoils for wind turbines
… terms of drag reduction. In addition to V-shaped riblets, skipped-tooth riblet configurations were also tested on the DU 96-W-180 airfoil. Results showed that the magnitude of drag reduction depended on the angle of attack, Reynolds number, riblet size, and riblet location and was highly airfoil …
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An experimental investigation of the effect of riblets on heat transfer in the incompressible, turbulent boundary layer over a flat plate
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1990.
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An investigation into the effect of longitudinal micro-striations and their profiles, on the drag of flat plates
… The idea that a longitudinally grooved surface ("riblets") could reduce the turbulent skin friction developed in part from the concept that the scales of fast-swimming sharks may have a surface structure that improves boundary-layer performance. Previously conducted experiments show that v-grooves …
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The influence of superhydrophobic surfaces on near-wall turbulence
… origins, reminiscent of drag reduction using riblets. The validity of slip-length models to represent textured superhydrophobic surfaces can resultantly be extended up to $L^+ \lesssim 20$. However, for $L^+ \gtrsim 25$ a non-linear interaction with the texture-coherent flow alters the …
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Turbulent drag reduction by anisotropic permeable substrates
… 180$, which is at least twice that obtained for riblets.
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Flows in Grooved Channels
… to the flow direction (longitudinal grooves or riblets) have been carried out. Mechanisms of drag generation for each case have been identified. Analytical solutions have been determined in the limit of long wavelength grooves in order to simplify identification of these mechanisms. It has been …
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Multiphase Flow Dynamics in Confined Domains—A DNS Study of Bubbly, Thermal and Riblet-Induced Turbulence
… pseudo-turbulence in buoyancy-driven flows, and riblets dictating transition dynamics in wall-bounded shear flows. By integrating high-resolution DNS, advanced interface-capturing techniques, and systematic parameter studies, the work identifies multiscale mechanisms—ranging from droplet …
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Control of the buffer and logarithmic layers in wall-bounded turbulent flows
… of small size. For the particular case of riblets, it has been proposed that their effect on the overlying flow could be reduced to an offset between the origins perceived by the streamwise and spanwise velocities, with the latter being the origin perceived by turbulence. Later results, …