On the three-dimensional wake flow behind a normal flat plate

2022 ◽  
Vol 34 (1) ◽  
pp. 013603
Author(s):  
Muk Chen Ong ◽  
Guang Yin
Keyword(s):  
Flat Plate ◽  
Three Dimensional ◽  
Wake Flow

The Wake Behind Two Intersecting Flat Plates

2014 ◽  
Author(s):  
Fatemeh Hoseini Dadmarzi ◽  
Vagesh D. Narasimhamurthy ◽  
Helge I. Andersson ◽  
Bjørnar Pettersen
Keyword(s):  
Reynolds Number ◽  
Flat Plate ◽  
Three Dimensional ◽  
Wake Flow ◽  
Flat Plates ◽  
Total Drag ◽  
Vortex Streets ◽  
Mean Pressure ◽  
The Mean ◽  
Plate Width

The wake flow behind two intersecting flat plates forming a cross is studied by means of direct numerical simulation (DNS) at low Reynolds number. The Reynolds number based on the plate width, d, and the inflow velocity, U0, is 100. The flat plate structure is in one plane. Away from the intersecting center part, vortex streets can be observed similar to the wake flow behind a single normal flat plate. On the other hand, the flow is completely three-dimensional in the vicinity of the intersecting region where the wakes from each of the two normal flat plates interact with each other. The mean pressure distribution on the structure is evaluated in order to study the total drag force as well as the local force distribution.

Three-Dimensional Effects of the Flow Normal to a Flat Plate at a High Reynolds Number

2012 ◽  
Author(s):  
Xinliang Tian ◽  
Muk Chen Ong ◽  
Jianmin Yang ◽  
Dag Myrhaug ◽  
Gang Chen
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Flat Plate ◽  
High Reynolds Number ◽  
Plate Thickness ◽  
Three Dimensional ◽  
Wake Flow ◽  
Plate Height ◽  
3D Effects ◽  
High Reynolds

Plate components are often found in offshore and marine structures, such as heave damping plates in spar platform and bilge keels in ships. Two-dimensional (2D) and three-dimensional (3D) numerical simulations are performed to investigate the 3D effects of the flow normal to a flat plate at a high Reynolds number (Re = 1:5×105, based on the height of the plate and the free stream velocity). The ratio of the plate thickness to the plate height is 0.02. The 2D simulations are carried out by solving the Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations with the k-ω Shear Stress Transport (SST) turbulence model, while the 3D simulations are carried out with the large-eddy simulation (LES) method. The hydrodynamic results (such as time-averaged drag coefficient, Strouhal number and mean recirculation length) are compared with the published experimental data. The near-wake flow structures are also discussed. The 3D simulation results are in good agreement with the published experimental data; however, the 2D simulations show a poor comparison with the experimental data. This shows that the 3D effects are important for the high Reynolds number flow normal to a flat plate.

Wake Flow of Single and Multiple Yawed Cylinders

2004 ◽  
Vol 126 (5) ◽  
pp. 861-870 ◽  
Author(s):  
A. Thakur ◽  
X. Liu ◽  
J. S. Marshall
Keyword(s):  
Computational Study ◽  
Three Dimensional ◽  
Side Wall ◽  
Wake Flow ◽  
Upstream Region ◽  
Two Dimensional ◽  
Cylinder Wake ◽  
Dimensional Approximation ◽  
The Face ◽  
Drag And Lift

An experimental and computational study is performed of the wake flow behind a single yawed cylinder and a pair of parallel yawed cylinders placed in tandem. The experiments are performed for a yawed cylinder and a pair of yawed cylinders towed in a tank. Laser-induced fluorescence is used for flow visualization and particle-image velocimetry is used for quantitative velocity and vorticity measurement. Computations are performed using a second-order accurate block-structured finite-volume method with periodic boundary conditions along the cylinder axis. Results are applied to assess the applicability of a quasi-two-dimensional approximation, which assumes that the flow field is the same for any slice of the flow over the cylinder cross section. For a single cylinder, it is found that the cylinder wake vortices approach a quasi-two-dimensional state away from the cylinder upstream end for all cases examined (in which the cylinder yaw angle covers the range 0⩽ϕ⩽60°). Within the upstream region, the vortex orientation is found to be influenced by the tank side-wall boundary condition relative to the cylinder. For the case of two parallel yawed cylinders, vortices shed from the upstream cylinder are found to remain nearly quasi-two-dimensional as they are advected back and reach within about a cylinder diameter from the face of the downstream cylinder. As the vortices advect closer to the cylinder, the vortex cores become highly deformed and wrap around the downstream cylinder face. Three-dimensional perturbations of the upstream vortices are amplified as the vortices impact upon the downstream cylinder, such that during the final stages of vortex impact the quasi-two-dimensional nature of the flow breaks down and the vorticity field for the impacting vortices acquire significant three-dimensional perturbations. Quasi-two-dimensional and fully three-dimensional computational results are compared to assess the accuracy of the quasi-two-dimensional approximation in prediction of drag and lift coefficients of the cylinders.

Three-dimensional heat transfer analysis of flat-plate oscillating heat pipes

2021 ◽  
pp. 117189
Author(s):  
Kimihide Odagiri ◽  
Kieran Wolk ◽  
Stefano Cappucci ◽  
Stefano Morellina ◽  
Scott Roberts ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Three Dimensional ◽  
Heat Pipes ◽  
Heat Transfer Analysis

Aerodynamic Measurements on the Interaction of Secondary Jets and Separation Bubble

2012 ◽  
Author(s):  
A. Samson ◽  
S. Sarkar
Keyword(s):  
Flat Plate ◽  
Large Scale ◽  
Separation Bubble ◽  
Three Dimensional ◽  
Leading Edge ◽  
Bubble Interactions ◽  
Separated Shear Layer ◽  
Bubble Length ◽  
Flow Visualizations ◽  
Turbulence Generation

The dynamics of separation bubble under the influence of continuous jets ejected near the semi-circular leading edge of a flat plate is presented. Two different streamwise injection angles 30° and 60° and velocity ratios 0.5 and 1 for Re = 25000 and 55000 (based on the leading-edge diameter) are considered here. The flow visualizations illustrating jet and separated layer interactions have been carried out with PIV. The objective of this study is to understand the mutual interactions of separation bubble and the injected jets. It is observed that flow separates at the blending point of semi-circular arc and flat plate. The separated shear layer is laminar up to 20% of separation length after which perturbations are amplified and grows in the second-half of the bubble leading to breakdown and reattachment. Blowing has significantly affected the bubble length and thus, turbulence generation. Instantaneous flow visualizations supports the unsteadiness and development of three-dimensional motions leading to formation of Kelvin-Helmholtz rolls and shedding of large-scale vortices due to jet and bubble interactions. In turn, it has been seen that both the spanwise and streamwise dilution of injected air is highly influenced by the separation bubble.

The Calculation of Train Slipstreams on Platform of Underground High-Speed Rail Station

2013 ◽  
Vol 842 ◽  
pp. 445-448
Author(s):  
Wei Chao Yang ◽  
Chuan He ◽  
Li Min Peng
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Horizontal Distribution ◽  
Wake Flow ◽  
Railway Tunnel ◽  
Long Distance ◽  
Near Wake ◽  
High Speed Rail ◽  
Numerical Work ◽  
Rail Station

This paper describes the results of numerical work to determine the flow structures of the slipstream and wake of a high speed train on platforms of underground rail station using three-dimensional compressible Euler equation. The simulations were carried out on a model of a simplified three-coach train and typical cross-section of Chinese high-speed railway tunnel. A number of issues were observed: change process of slipstreams, longitudinal and horizontal distribution characteristics of train wind. Localized velocity peaks were obtained near the nose of the train and in the near wake region. Maximum and minimum velocity values were also noticed near to the nose rear tip. These structures extended for a long distance behind the train in the far wake flow. The slipstream in platform shows the typical three-dimensional characteristics and the velocity is about 4 m/s at 6 m away from the edge of platform.

Measurements of wake flow behind a flat plate with fractal edge geometries

2020 ◽  
Vol 2020 (0) ◽  
pp. S05128
Author(s):  
Tatsuo USHIJIMA ◽  
Yutaka HASEGAWA ◽  
Takuma MIZUTANI
Keyword(s):  
Flat Plate ◽  
Wake Flow
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