On the scaling of air layer drag reduction

Web1 de fev. de 2013 · Abstract Air-induced drag reduction was investigated on a 12.9 m long flat plate test model at a free stream speed of $6. 3~\\mathrm{m} ~{\\mathrm{s} }^{- 1} $ . … Web24 de dez. de 2024 · In this paper, we focus on an economic and ecological assessment of the effect of persistent air layers under water (Salvinia Effect [7,10]) for drag reduction and consequently fuel saving. Although bionics and biomimetics play an important role in research, economy and public awareness, very few data are available concerning the …

Fluids Free Full-Text Dimples for Skin-Friction Drag Reduction ...

Web3 de jan. de 2024 · uneven micro/nanostructures of lotus leaves. The superhydrophobicity and drag reduction ratios at low velocities are highly improved using a laser ablation method on metal substrates. However, unstable air layers trapped on superhydrophobic surfaces are usually cut away by a high-velocity flow, which greatly reduces the drag … Web1 de dez. de 2012 · When gas is injected beneath a horizontal plate, a transition can take place from a bubbly flow to that of a gas layer. Elbing et al. (2008) showed that a … soheil vahedi cuetracker https://bennett21.com

Active and Passive Turbulent Boundary-Layer Drag Reduction

Web3 de out. de 2024 · Air lubrication by means of a bottom cavity is a promising method for ship drag reduction. The characteristics of the bottom cavity are sensitive to the flow field around the ship hull and the effect of drag reduction, especially the depth of the bottom cavity. In this study, a ship model experiment of a bulk carrier is conducted in a towing … Web8 de nov. de 2024 · The air layer drag reduction (ALDR) of an axisymmetric body in oscillatory motions is investigated in this paper with open source toolbox OpenFOAM. The unsteady Reynolds-averaged Navier-Stokes (URANS) equations are used to determine the viscous flow and the volume of fluid (VOF) model is adopted to capture the interface of … Web1 de jul. de 2024 · Air Layer Drag Reduction (ALDR) is a promising engineering method for reducing ship fuel consumption, especially for large, low-speed displacement … soheil tavakoli architecture

Experiment and simulation on air layer drag reduction of high …

Category:Disturbances to Air-Layer Skin-Friction Drag Reduction at High …

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On the scaling of air layer drag reduction

Numerical Study on the Behavior of Air Layers Used for Drag …

Web1 de jan. de 2010 · Request PDF On Jan 1, 2010, J.K. Choi and others published Numerical Study on the Behavior of Air Layers Used for Drag Reduction Find, read … WebTwo distinct drag-reduction phenomena were investigated; bubble drag reduction (BDR) and air-layer drag reduction (ALDR).The streamwise distribution of skin-friction drag reduction was monitored with six skin-friction balances at downstream-distance-based Reynolds numbers to 220 million and at test speeds to 20.0msinitial zone1.

On the scaling of air layer drag reduction

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Web1 de mai. de 2024 · In addition, once ALDR was established: friction drag reduction in excess of 80% was observed over the entire smooth model for speeds to 15.3 m s(-1); the critical volumetric flux of air required ... Web10 de abr. de 2024 · Superhydrophobic surfaces could repel water due to the capillary force associated with surface roughness, which has a large range of applications, such as underwater drag reduction, heat transfer enhancement, oil/water separation, and so on. However, the engineering applications of superhydrophobic surfaces rely on the stability …

Web7 de abr. de 2024 · Research on the drag reduction of micro-grooved walls has been carried out in pipe flow and channel flow. Early systematic investigations began in the 1980s, 6,9 6. M. J. Walsh, “ Turbulent boundary layer drag reduction using riblets,” in AIAA 20nd Aerospace Sciences Meeting, Orlando, Florida, 11–14 January 1982 ( AIAA, 1982). 9. Web26 de ago. de 2016 · We study both experimentally and theoretically the descending motion due to gravity of a fluid drop surrounded by another immiscible fluid in a confined …

Web7 de abr. de 2024 · Research on the drag reduction of micro-grooved walls has been carried out in pipe flow and channel flow. Early systematic investigations began in the … Web15 de jan. de 2024 · The drag reduction rate in this study reached 20%. The results demonstrate that a continuous air film on superhydrophobic surfaces plays an important …

Web11 de abr. de 2024 · In this paper, we study the aerodynamic shape of dandelion, derive the scaling law of resistance, determine the Vogel exponent. In particular, we find that the …

Webmaximum level of drag reduction, typically in excess of 80-90%, where the increased gas injection yielded little or no improvement in skin-friction reduction. slow video 2014 torrentWeb20 de mai. de 2024 · Abstract The correlation between drag variation and rear surface pressure of an Ahmed body with a slant angle of 25° is experimentally studied. The body is forced with several independent steady blowings deployed around the rear window and the vertical base. Several combinations of the independent blowings are investigated, which … soheil wish genshinWeb6 de mai. de 2024 · This study investigates experimentally the drag reduction of the micro-grate patterned superhydrophobic (SHPO) surface compared with its smooth flat counterpart in turbulent boundary layer flow. Two SHPO surfaces were examined, with the same air fraction but different grate spacings. Both surfaces were fabricated using ultra-precision … slow victories cookbookWeb9 de jul. de 2024 · Elbing B. R., Winkel E. S., Lay K. A. et al. Bubble-induced skin-friction drag reduction and the abrupt transition to air-layer drag reduction [J]. Journal of Fluid Mechanics, 2008, 612: 201–236. Article Google Scholar Ceccio S. L.. Friction drag reduction of external flows with bubble and gas injection [J]. slow video 2014 hdWeb1 de jul. de 2024 · When present, flow separation prevails, since friction drag is subdominant at large speed. In such conditions, the traditional approach to drag control still mostly relies on body streamlining, i.e., body shape optimization aimed at preventing/limiting flow separation. sohe internshipWeb31 de ago. de 2024 · 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. The approaches have generally … soheil wish genshin impactWeb16 de mar. de 2024 · Cavitating flow near free surface is a complicated issue and may provide new inspiration on high-speed surface cruising. This study observes stable supercavitating flow as a new phenomenon in a launch experiment of axisymmetric projectile when the upper side of the projectile coincides with the free surface. sohei pathfinder