2 edition of Turbulent drag reduction by passive means found in the catalog.
Turbulent drag reduction by passive means
|Contributions||Royal Aeronautical Society.|
In this review, the generation mechanisms of skin friction drag under the action of disturbing the turbulent boundary layer are discussed, and the main active drag reduction methods are summarized. Accession Number: ADP Title: Turbulent Skin-Friction Drag Reduction By Active and Passive 1. Everything you wanted to Know about Riblets, LEBUs and Other Devices, Corporate Author: OFFICE NATIONAL D'ETUDES ET DE RECHERCHES AEROSPATIALES TOULOUSE (FRANCE) Personal Author(s): Coustols, E. ; Savill, A. M. Report Date: MAR
The mean square slope as the driving roughness parameter in promoting plastron stability, and suggest methods by which it may be increased in order to optimize drag-reducing performance. The air plastron captured by a passive superhydrophobic surface represents one . Passive scalar transport in turbulent channel flow of viscoelastic dilute polymer solutions exhibiting drag reduction (DR) is studied using direct numerical simulations for DR values up to %. DR is accompanied by the stabilization of low‐speed streaks in the buffer layer that are primarily responsible for the streamwise heat transport.
Turbulence management represents another class of means for reduction of friction drag or, more in general, for turbulent boundary layer manipulation (Slooff, ). For aeronautical. Drag reduction in turbulent flow on a passive superhydrophobic surface is small at low Re’s and increases to a maximum of 22% at Re = 80,, whereas the turbulent drag reduction on our low-temperature Leidenfrost surface approaches 80 to 90% at much lower Re’s. The regression of Eq.
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Turbulence Control by Passive Means: Proceedings of the 4th European Drag Reduction Meeting (Fluid Mechanics and Its Applications) th Edition by E. Coustols (Editor) ISBN Turbulence Control by Passive Means Effects of Longitudinal Pressure Gradients on Turbulent Drag Reduction with Riblets.
Pages Choi, Kwing-So. Book Title Turbulence Control by Passive Means Book Subtitle Proceedings of the 4th European Drag Reduction Meeting Editors. Turbulence Control by Passive Means Proceedings of the 4th European Drag Reduction Meeting. Editors (view affiliations) E. Coustols; Conference proceedings.
43 Citations; k Downloads; Part of the Fluid Mechanics and its Applications book series (FMIA, volume 4) Log in to check access. Buy eBook. USD Instant download. This has led to an extensive search for both active and passive methods for drag reduction 1. Here we report the results of a series of wind-tunnel experiments that demonstrate a passive means of Cited by: Turbulent drag reduction by passive mechanism and passive methods for drag reduction.
Here we report the results of a series of wind-tunnel experiments that demonstrate a passive means of. There is currently considerable academic and industrial interest in the possibility of controlling the eddy structure of turbulent boundary layers by passive means (either to reduce skin friction drag, self-noise and mixing or alternatively to increase mixing and heat transfer), both for the practical benefits that may be achieved and for the insight such studies can provide into the mechanisms and dynamics of.
adshelp[at] The ADS is operated by the Smithsonian Astrophysical Observatory under NASA Cooperative Agreement NNX16AC86A. A 50 year journey through flow control strategies that seek to achieve viscous drag reduction in turbulent boundary layers is presented.
These are shown to focus on different mechanisms underlying coherent motions that have been observed in the early period of turbulent boundary-layer research. Changes in the structure of turbulence 7 Degradation 7 Definition 8 Representation of data under drag reducing flow conditions 9 The friction factors 10 The mean velocity profiles 13 A short survey ofreviews on the subject 14 A short survey of the contents of this book Turbulent drag reduction by passive mechanism.
This has led to an extensive search for both active and passive methods for drag reduction. that demonstrate a passive means of effectively. Turbulent drag reduction by passive mechanisms. Sirovich, L. Karlsson, S. Abstract. In many situations involving flows of high Reynolds number (where inertial forces dominate over viscous forces), such as aircraft flight and the pipeline transportation of fuels, turbulent drag is an important factor limiting performance.
The reduction of turbulent drag in wall-bounded turbulent flows represents one of the great challenges in fluid mechanics, as well as in many industry applications. In these years, the interest of this subject is steadily growing, because even a little bit of reduction can lead to a dramatic energy saved in flow systems, such as oil pipelines.
Flow control aims at minimizing this drag force, and the subject is explicitly or implicitly interwoven in every chapter of this book. Delaying laminar-to-turbulence transition (Chapter 6) is usually sought in order to benefit from the much lower skin friction associated with laminar boundary layers.
The combination of passive, riblet structures, and active drag reduction means, transversal surface waves, has been investigated in a turbulent boundary layer flow over a flat plate.
The semi-circular riblet structure at a height over width ratio h /. European Drag Reduction Meeting (4th: Lausanne, Switzerland). Turbulence control by passive means. Dordrecht ; Boston: Kluwer Academic Publishers, © (OCoLC) Online version: European Drag Reduction Meeting (4th: Lausanne, Switzerland).
Turbulence control by passive means. Get this from a library. Turbulence Control by Passive Means: Proceedings of the 4th European Drag Reduction Meeting. [E Coustols] -- In the last decades, a lot of effort has been directed towards manipulation of turbulent boundary layers by passive devices such as external manipulators (thin flat plates or aerofoil section devices.
Friction Drag Reduction by Injection of Polyethyleneoxide Solution in a Turbulent Boundary Layer Through Slot and Perforated Section V. Mamonov, B. Mironov, S. Panov Pages Drag Reduction by Other Means. simulate turbulent ﬂows over a dimpled surface for a wide range of Reynolds number, and (ii) Determining the correlation be-tween the drag property and the mean ﬂow pattern.
The present simulations in a channel domain are able to reproduce the qual-itative trend of percentage drag reduction as a function of the. The fidelity of the method has been testified by simulating turbulent flow over thin riblets of thickness to spacing ratio of Five cases with different spacing, within which a drag reduction and drag increase are expected to occur, have been investigated.
The drag reduction trend shows excellent comparison with that of Bechert et al. Freeman Scholar Review: Passive and Active Skin-Friction Drag Reduction in Turbulent Boundary Layers 2 June | Journal of Fluids Engineering, Vol.No.
9 Control of Turbulence. A. Poll and P. G. Westland, in Proceedings of the Symposium on Turbulent Drag Reduction by Passive Means (The Royal Aeronautical Society, London, ). Google Scholar * The paper was first presented at an international conference on "Turbulent Drag Reduction by Passive Means" organized by the Royal Aeronautical Society and held at the Society's headquarters in London September It is here reprinted by permission of the Society.
Direct numerical simulations are performed to study the drag reduction effect in turbulent flow along a cylinder by the circumferential oscillating Lorentz force at the Reynolds number Re τ = based on the reference friction velocity and the thickness of the boundary layer.
The maximum drag reduction rate obtained in the present work is %.