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Simulation of flow around cylinder Actuated by DBD Plasma

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Plasma Science and Technology 2016年第7期18卷 768-774页

作者：王玉玲高超武斌胡旭 National Key Laboratory of Science and Technology on Aerodynamic Design and Research Northwestern Polytechnical University

The electric-static body force model is obtained by solving Maxwell＇s electromagnetic equations. Based on the electro-static model, numerical modeling of flow around a cylinder with a dielectric barrier discharge （DBD） plasma effect is also presented. The flow streamlines between the numerical simulation and the particle image velocimetry （PIV） experiment are consistent. According to the numerical simulation, DBD plasma can reduce the drag coefficient and change the vortex shedding frequencies of flow around tile cylinder.

关键词： dielectric-barrier-discharge plasma body force flow around cylinder

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EXPERIMENTS ON flow around A cylinder IN A SCOURED CRANNEL BED

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International Journal of Sediment Research 2001年第4期 431-444页

作者： I. ISTIARTO and W.H. GRAF 1 Res. Asst., Lab. de recherches hydrauliques, Ecole Polytechnique Federale, Lausanne, Switzerland. E-mail: adhy.kurniawan@epfl.ch or istiarto@tsipil.ugm.ac.id 2 Prof, Lab. de recherches hydrauliques, Ecole Polytechnique Federal

The flow pattern around a cylinder, installed in a scourd channel bed, was experimentally investigated. Detailed measurements of the instantaneous 3D velocities were performed by using an Acoustic Doppler Velocity Profiler (ADVP), from which the profiles of the time~averaged velocities and turbulence stresses were obtained. It is shown that the influence of thC cylinder and of the scour hole alters the approach flow; this is essentially confined to the viciulty of the cylinder and to the inside of the scour hole. The horseshoe vortex is measured as a flow reversal inside the scour hole, formed by the downward flow along the cylinder face and the reversed flow at the scour bed.

关键词： Open channel flow flow around cylinder Local scour Experiments

Stress boundary layers in the viscoelastic flow past a cylinder in a channel:limiting solutions

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Acta Mechanica Sinica 2005年第4期21卷 311-321页

作者： Yurun Fan Huayong Yang Roger I. Tanner State Key Laboratory of Fluid Power Control and Transmission Zhejiang University Hangzhou 310027 China School of Aerospace Mechanical and Mechatronic EngineeringUniversity of Sydney NSW 2006 Australia

The flow past a cylinder in a channel with the aspect ratio of 2 ： 1 for the upper convected Maxwell （UCM） fluid and the Oldroyd-B fluid with the viscosity ratio of 0.59 is studied by using the Galerkin/Least-square finite element method and a p-adaptive refinement algorithm. A posteriori error estimation indicates that the stress-gradient error dominates the total error. As the Deborah number, De, approaches 0.8 for the UCM fluid and 0.9 for the Oldroyd-B fluid, strong stress boundary layers near the rear stagnation point are forming, which are characterized by jumps of the stress-profiles on the cylinder wall and plane of symmetry, huge stress gradients and rapid decay of the gradients across narrow thicknesses. The origin of the huge stress-gradients can be traced to the purely elongational flow behind the rear stagnation point, where the position at which the elongation rate is of 1/2De approaches the rear stagnation point as the Deborah number approaches the critical values. These observations imply that the cylinder problem for the UCM and Oldroyd-B fluids may have physical limiting Deborah numbers of 0.8 and 0.9, respectively.

关键词： Viscoelastic flow Stress boundary layer flow around cylinder Adaptive finite element

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The flow characteristics around bridge piers under the impact of a ship

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Journal of Hydrodynamics 2020年第6期32卷 1165-1177页

作者： Yan-fen Geng Hua-qiang Guo Xing Ke School of Transportation Southeast UniversityNanjing211189China

The complicated flow structure around the pier threatens the safe navigation of ships.This paper studies the mechanism of the flow with a ship around the pier,passing or not passing and with consideration of the interval between the ship and the pier.The flow field model and the moving ship model are constructed by the six degrees of freedom(6DOF)solver combined with the virtual unit immersed boundary method and the level set method,both of which are based on the three-dimensional Navier-Stokes equations.The simulation results show that the ship significantly influences the flow around the pier,increasing the flow velocity by 50%to 140%.Away from the bridge pier,the cross-flow velocity decreases.The cross-flow velocity near the side of the pier also increases but in the opposite direction.The ship is affected by the negative yaw moment because of the reverse cross-flow between the pier and the ship.The size of the ship has an important impact on the extent of the affected flow areas but the velocity distribution is roughly in the same shape.The results show double impacts of ship and pier should be considered when determining the safe area of navigation.

关键词： Bridge pier flow around cylinder moving ship model

Experimental study on flow pattern of cylinder turbulent wake in a shallow-water layer

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Progress in Natural Science:Materials International 2000年第9期 49-54页

作者：李玲李玉梁祁雪春陈嘉范 Beijing 100084 China Department of Hydraulic Engineering Tshinghua University

A series of experiments were conducted to investigate the wakes of circular cylinder in shallow-water flow. Using DPIV (digital particle imaging velocimetry) system, the detailed measurement of turbulent wake around a cylinder with diameter of 1.27 m was made under the condition of many different characteristic coefficients S. The streamline figures of wake flow have been given. The measured results show that the characteristic coefficient S is the unique factor deciding the flow pattern around a cylinder in shallow water layer and the value 0.45 is the critical value of transition from vortex street to steady recirculating flow. At the same time, the mechanism of cylinder turbulent wakes in a shallow water layer is given.

关键词： shallow water layer flow around cylinder turbulent wake digital particle imaging velocimetry (DPI).