Skin Friction Measurements using Oil Film Interferometry and Laser Doppler Anemometry ... such as viscous drag reduction. Oil film interferometry (OFI) and laser Doppler anemometry (LDA) measurements have been carried out at several locations downstream of the wall jet exit. Velocity profiles from the LDA measurements have been analyzed using a NON-UNIFORM SLOT INJECTION (SUCTION) INTO WATER BOUNDARY ... be delayed by non-uniform slot suction and also by moving the slot downstream but the effect of non-uniform slot injection is just the opposite. The heat transfer rate is found to depend strongly on viscous dissipation but the skin friction is little affected by it. Numerical Investigation of Flow Control by Suction and ... The case studied is the flow field over a subsonic airfoil with four suction and injection slots on the suction side of the airfoil. Five different angles of attack, 0, 5, 10, 13.3 and 20 with the Mach ... drag reduction, lift enhancement and flow-induced noise suppression. By controlling the flow, the fuel ... skin-friction drag for a laminar ... Center for Turbulence Research Annual Research Briefs 2010 ...
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In this report, cooling and skin-friction data from direct measurements downstream of flush slots are compared with results previously reported for step slots. The multiple slot effect on skin friction is also examined. Pre dictions from a compressible, turbulent-boundary-layer computer program have SKIN FRICTION REDUCTION IN SUPERSONIC FLOW BY INJECTION ... SKIN FRICTION REDUCTION IN SUPERSONIC FLOW BY INJECTION THROUGH SLOTS, POROUS SECTIONS AND COMBINATIONS OF THE TWO By Joseph A. Schetz and Johannes vanOvereem Virginia Polytechnic Institute and State University INTRODUCTION Fluid injection schemes for thermal protection and, more recently, skin Skin friction reduction by slot injection at Mach 0.8 Download Citation on ResearchGate | Skin friction reduction by slot injection at Mach 0.8 | Surface skin friction, boundary layer profiles and turbulent intensity due to axially symmetric ... Direct measurements at Mach 6 of turbulent skin-friction ...
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The Seeker is primarily searching for existing technologies or research studies, outside of the aircraft industry, that provide surface friction reduction in fluid mediums and have potential to be translated to the aircraft industry for skin friction reduction. Other sources of aircraft drag reduction … Polymer/riblet combination for hydrodynamic skin friction reduction … Aug 29, 1995 · injecting a drag reducing polymer into the individual groove valleys at multiple points along each groove such that amounts of the polymer needed to reduce skin friction along the entire length of the surface are minimized, infecting the drag reducing polymer by means of an array of slots or holes angled such that the injected polymer is Chapter 2.22 - Determination of Flow Characteristics of Multiple Slot Jet Impingement Cooling … In that study, the flow characteristics and flow distribution patterns of a single slot jet as well as a multiple slot jet located at the upper wall of a two-dimensional channel were analyzed numerically. The pressure distribution of the channel and the variation in skin friction coefficients along the impingement surface plate were also presented. How to Reduce Friction between Surfaces
Skin friction reduction by slot injection at Mach 0.8
some level of reduction to the skin friction drag. For reasons that will be discussed later, all three porthole cases exhibit some lesser ability to reduce the skin friction drag generated along the surface downstream of the step, with the closest porthole spacing providing performance nearest to that of the slot … Engineered Surfaces, Materials and Coatings for Aircraft Drag Reduction … The Seeker is primarily searching for existing technologies or research studies, outside of the aircraft industry, that provide surface friction reduction in fluid mediums and have potential to be translated to the aircraft industry for skin friction reduction. Other sources of aircraft drag reduction … Polymer/riblet combination for hydrodynamic skin friction reduction …
control; e.g., polymer injection1 or slot suction, 3) effi-cient propulsion; e.g., a wake propeller or a suction slot with a stern jet,2 and 4) efficient steering control consis-tent with hydrodynamic stability. Items 1 and 2 attempt to reduce skin friction and pres-sure drag while item 3 attempts to extract energy lost to
Oct 2, 2018 ... possibility of skin friction reduction through modification of the structure of the turbulence in the boundary layer ...... the use of multiple slots, the. Influence of Surface Roughness on Polymer Drag Reduction - DTIC Feb 15, 2019 ... of the boundary layer resulting in a reduction in skin-friction drag. Substances used for .... This was a slot injector inclined at a shallow 5.70 from the model surface and contracting ... Multiple calibrations were performed on the ... Hypervelocity Skin-Friction Reduction by Boundary-Layer Combustion ... (2018) Analysis and reduction of skin-friction in a rocket-based combined-cycle engine flow path operating from ... Slot Injection of Hydrogen into a Supersonic Air Flow. ... Hypersonic Viscous Drag Reduction Via Multi-Porthole Injector Arrays . Submarines - Polymer Drag Reduction - GlobalSecurity.org Nov 7, 2011 ... ... which have shown 70-80% reduction in skin-friction drag coefficient in the ... Ionic and non-ionic surfactants can also offer similar drag reduction as .... amount or more additive being ejected from multiple slots along the ...
Polymer/riblet combination for hydrodynamic skin friction ... injecting a drag reducing polymer into the individual groove valleys at multiple points along each groove such that amounts of the polymer needed to reduce skin friction along the entire length of the surface are minimized, infecting the drag reducing polymer by means of an array of slots or holes angled such that the injected polymer is ... Skin Friction Measurements using Oil Film Interferometry ... Skin Friction Measurements using Oil Film Interferometry and Laser Doppler Anemometry ... such as viscous drag reduction. Oil film interferometry (OFI) and laser Doppler anemometry (LDA) measurements have been carried out at several locations downstream of the wall jet exit. Velocity profiles from the LDA measurements have been analyzed using a Microbubble Drag Reduction in Liquid Turbulent Boundary ... Microbubble Drag Reduction in Liquid Turbulent Boundary Layers. Charles L. Merkle and ... the magnitude of the skin friction reduction increases as the volume of bubbles in the boundary layer is increased until a maximum skin friction reduction of typically 80–90% of the undisturbed skin friction level is reached. ... Microbubble Drag ...