Improvement of Discharge Flow Structure by Bluff-Body Insert and Size Reduction of a Mixed-Flow Irrigation Pump

The trend of automotive design induces vertical shape in the region of the rear tailgate, which leads to important aerodynamic losses in the rear back of vehicles. Experimental wake analysis performed behind a square back bluff body shows influence of the vortex transport in the mixing layers backward the detachment region. It is therefore important to carry on studies on turbulent wake understanding in order to find solutions for drag reduction with the current vehicle design. This paper presents LES simulation results computed in order to describe transport of large vortices produced in the 3D wake structure behind a square back bluff body. Prior to this result analysis, we will show comparison with experimental results, helpful to validate these transient computations, performed with different pulsed jets implemented at the top end of the square back, close to the separation zone. Analysis of these computations results will also focus on the relation between amplitude of the flow structure and Cd results.

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Flow structure around a 3D bluff body in ground proximity: A computational study

Journal of Wind Engineering and Industrial Aerodynamics ◽

10.1016/0167-6105(93)90355-r ◽

1993 ◽

Vol 46-47 ◽

pp. 791-800 ◽

Cited By ~ 4

Author(s):

Siva Parameswaran ◽

Ilker Kiris ◽

Richard Sun ◽

Mark Gleason

Keyword(s):

Flow Structure ◽

Bluff Body ◽

Computational Study

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Performance enhancement of single dielectric barrier discharge flow control actuators by means of rear linking tunnels on a reference bluff body using CFD

Journal of Wind Engineering and Industrial Aerodynamics ◽

10.1016/j.jweia.2020.104488 ◽

2021 ◽

Vol 209 ◽

pp. 104488

Author(s):

S. Karimi ◽

B. Mohammadikalakoo ◽

P. Schito

Keyword(s):

Flow Control ◽

Dielectric Barrier Discharge ◽

Bluff Body ◽

Performance Enhancement ◽

Barrier Discharge ◽

Dielectric Barrier ◽

Discharge Flow

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Experimental Investigation of Confined Swirling Flow and Its Interaction With a Bluff Body

Journal of Fluids Engineering ◽

10.1115/1.4044482 ◽

2019 ◽

Vol 142 (1) ◽

Author(s):

Zhang Tianxing ◽

Mohamed Alshehhi ◽

Lyes Khezzar ◽

Yakang Xia ◽

Nabil Kharoua

Keyword(s):

Flow Structure ◽

Pipe Flow ◽

Laser Doppler Velocimetry ◽

Bluff Body ◽

Swirling Flow ◽

Reynolds Numbers ◽

Working Fluid ◽

Doppler Velocimetry ◽

Mean Square ◽

The Mean

Abstract Detailed laser Doppler velocimetry (LDV) measurements of profiles of mean axial and tangential velocities and their corresponding root-mean-square (RMS) components in confined turbulent swirling pipe flow with and without the presence of a conical bluff body have been conducted. The working fluid was water and the Reynolds number based on the bulk velocity inside the pipe was equal to 40,850. The main focus of the study was to document the interaction between turbulent swirling flow inside a pipe and in the presence of a conical bluff body. The flow structure was found in all cases to be composed of a forced-free vortex. The swirl decay was exponential for Reynolds numbers of 40,850 and 14,450. The effect of the presence of the bluff body on the flow is limited to a short region upstream of it; so that the effect on the flow structure and strength of swirl upstream can be considered negligible. The flow around the bluff body adopts a different structure where the mean axial and tangential velocities tend to assume uniform profiles with turbulence activity limited to the region close to the surface of the bluff body.

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INVESTIGATION ON FLOW STRUCTURE BEHIND A RING BY IMPLEMENTING OPTICAL PARTICLE CHARACTERIZATIONS

International Journal of Modern Physics B ◽

10.1142/s0217979206041604 ◽

2006 ◽

Vol 20 (25n27) ◽

pp. 4511-4516

Author(s):

CHEOL WOO PARK

Keyword(s):

Flow Structure ◽

Bluff Body ◽

Water Channel ◽

Cross Flow ◽

Circular Ring ◽

Outer Side ◽

Mean Velocity ◽

Circulating Water ◽

Image Velocimetry ◽

Bluff Body Wake

The flow structure behind circular and elliptical type rings embedded in a cross-flow was investigated experimentally using a particle image velocimetry (PIV), implementing optical particle characterizations. The experiments were performed in a circulating water channel with a test section of 0.2m height × 0.3m width × 1.2m length. The Reynolds number based on the ring hoop cord length is about Re =1200. The velocity fields near the ring hoop were measured using the two-frame cross-correlation PIV method. As a result, the flow near the sharp-edged end of ring hoop ascends fast and showed a conventional vortical structure appeared in a bluff body wake. In the mean velocity field behind a circular ring, there were two large vortices rotating in different directions from each other in the near wake regime caused by the interaction between the central jet flow and the entrained ambient fluids from outer side of ring hoop.

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