... intensity is reduced, however, in the near wake downstream, there is an increase in axial turbulence intensity attributed to the wake of the cylinder. turbulent boundary layer drag reduction turbulence Proceedings of the ASME 2024 Fluids Engineering Division Summer Meeting FEDSM2024 July 15-17...

... Abstract There is a need for fuel-efficient vehicles to reduce greenhouse emission and minimize the range problem of electric vehicles. Aerodynamic drag reduction provides one of the cheapest but effective alternatives. Therefore, the development and analysis of new passive strategies that can...

... Proceedings of the ASME 2021 Fluids Engineering Division Summer Meeting FEDSM2021 August 10-12, 2021, Virtual, Online FEDSM2021-61461 PASSIVE DRAG REDUCTION TECHNOLOGY USING MICROFIBER COATINGS Mitsugu Hasegawa1, Hirotaka Sakaue1 1University of Notre Dame, Notre Dame, IN, USA ABSTRACT passive flow...

... is addressed in this research. Furthermore, the textures disrupt the thermal boundary layer, which can boost thermal transport through recirculation mixing. However, the stagnant fluid trapped within the grooves has weak convective heat transfer. So far, the results have been promising and a drag reduction...

... Abstract Practical implementation of ship drag reduction techniques can lead to substantial fuel savings and lessening environmental impacts of maritime transportation. One of such technologies is based on injecting air underneath ship hulls, which results in the formation of thin air cavities...

... shown formation of microbubble clusters intermittently, which has Coulomb potential due to negative electric charge on bubble interfaces. microbubble turbulent boundary layer drag reduction multiphase flow flow visualization VISUALIZATION OF MICROBUBBLE DISTRIBUTION INSIDE TURBULENT...

... Abstract It has been widely expected that the pulsating control can reduce friction drag in various fluid systems. In order to maximize its effect, a prediction tool of drag reduction using pulsating control is required. The present study aims at the prediction of the drag reduction rate...

... Abstract Drag reduction effect by traveling wavy wall deformation control in turbulent pipe flow was experimentally investigated. From the visualization, we confirmed the downstream traveling wave although it was not uniform in the circumferential direction. When the frequency is 110 Hz...

... pressure and velocity field are measured. In the result of aerodynamic force measurement, driving plasma actuator successfully achieves 3% drag reduction at the most. Flow field measurement of total pressure and two-component velocity shows the difference of vortex structure near the rear end between off...

... An experimental study of a new three-dimensional (3-D) riblet has been carried out. The lateral spacing of our 3-D riblet surface is sinusoidally varied in the streamwise direction (see Fig. 3). In the comparison of the optimal two-dimensional (2-D) blade riblet which shows 9.9% drag reduction...

... coefficient can be decreased by 2%, the aerodynamic cooling drag coefficient by more than 50% and the lift coefficient by 5%. Finally, new designs of aerodynamic drag reduction, based on the combined effects of the different investigated parameters, are proposed. Aerodynamic Drag reduction Simplified...

...turbulent boundary layer, which is a typical external Proceedings of FEDSM2007 5th Joint ASME/JSME Fluids Engineering Conference July 30-August 2, 2007 San Diego, California USA the mean velocity scaled by the friction velocity in- creases with increasing the amount of drag reduction...

... 26 03 2009 Turbulent drag reduction realized by hydrogen microbubbles was investigated experimentally. A method of generating microbubbles of 10–60μm diameter by water electrolysis was established. Experiments were performed using a water circulating tunnel. Microbubbles generated...

... 26 03 2009 This paper is a progress report of a research project toward practical use of air bubble injection as a drag reduction device for ships. Air bubbles injected into the turbulent boundary layer in water flow are well known to have significant skin friction reduction effect...

...Proceedings of FEDSM2007 5th Joint ASME/JSME Fluids Engineering Conference July 30-August 2, 2007 San Diego, California USA tion and for several pipes (4m long) with different diameters. In the case of high concentration conditions (500 and 750ppm), the range of drag reduction without heat exchange...

... pressure and velocity is high only for the streamwise component of the velocity vector for single phase flow (no microbubbles in the flow). A practical application of these measurements is obtaining data and information to better describe the mechanism responsible for the microbubble drag reduction...

... of compliant coatings has been known as the drag reduction means of the skin-friction and was studied by many researchers for 50 years. However the mechanism of drag reduction is not clarified. In this study, experimental study was conducted using compliant walls made of silicone gel to investigate...

... the skin-friction drag when opposition control is carried out with appropriate timing. turbulence boundary layers flow control drag reduction Proceedings of ASME FEDSM'02 2002 ASME Fluids Engineering Division Summer Meeting RB controlled with a relatively simple control scheme. For example...

... Base flow Near wake Unsteady flow Drag reduction This paper discusses experimental results aimed at defining a base drag reduction device based on splitter plates. The unsteady 3D nature of the flow is studied by Schlieren photographies, particle image velocimetry and measurement...

... 04 03 2009 The investigation results of the supercavitation for high speed motion of prolate axisymmetric bodies in water are presented. The cavitation drag forming and drag reduction problems are considered on base studying of the peculiarities of the supercavitation flows...