scholarly journals A numerical analysis of unsteady separated flow by vortex shedding model. 2nd report Flow around a circular cylinder.

1986 ◽  
Vol 52 (476) ◽  
pp. 1600-1607 ◽  
Author(s):  
Takaji INAMURO ◽  
Takeshi ADACHI
Keyword(s):  
Numerical Analysis ◽  
Circular Cylinder ◽  
Vortex Shedding ◽  
Separated Flow ◽  
Unsteady Separated Flow

Influence of a Magnetic Obstacle on Forced Convection in a Three-Dimensional Duct With a Circular Cylinder

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Xidong Zhang ◽  
Hulin Huang ◽  
Yin Zhang ◽  
Hongyan Wang
Keyword(s):  
Pressure Drop ◽  
Circular Cylinder ◽  
Vortex Shedding ◽  
Three Dimensional ◽  
Separated Flow ◽  
Optimum Conditions ◽  
Nusselt Numbers ◽  
Maximum Value ◽  
Wide Range ◽  
The Mean

The predictions of flow structure, vortex shedding, and drag force around a circular cylinder are promoted by both academic interest and a wide range of practical situations. To control the flow around a circular cylinder, a magnetic obstacle is set upstream of the circular cylinder in this study for active controlling the separated flow behind bluff obstacle. Moreover, the changing of position, size, and intensity of magnetic obstacle is easy. The governing parameters are the magnetic obstacle width (d/D = 0.0333, 0.1, and 0.333) selected on cylinder diameter, D, and position (L/D) ranging from 2 to 11.667 at fixed Reynolds number Rel (based on the half-height of the duct) of 300 and the relative magnetic effect given by the Hartmann number Ha of 52. Results are presented in terms of instantaneous contours of vorticity, streamlines, drag coefficient, Strouhal number, pressure drop penalty, and local and average Nusselt numbers for various magnetic obstacle widths and positions. The computed results show that there are two flow patterns, one with vortex shedding from the magnetic obstacle and one without vortex shedding. The optimum conditions for drag reduction are L/D = 2 and d/D = 0.0333–0.333, and under these conditions, the pressure drop penalty is acceptable. However, the maximum value of the mean Nusselt number of the downstream cylinder is about 93% of that for a single cylinder.

Numerical Analysis on Effect of Jet Injection on Vortex Shedding for Flow Over a Circular Cylinder

2018 ◽  
Vol 44 (2) ◽  
pp. 1475-1488 ◽  
Author(s):  
S. Karthikeyan ◽  
S. Senthilkumar ◽  
B. T. Kannan ◽  
U. Chandrasekhar
Keyword(s):  
Numerical Analysis ◽  
Circular Cylinder ◽  
Vortex Shedding ◽  
Jet Injection

Aerodynamic characteristics of an unsteady separated flow

1979 ◽  
Author(s):  
M. FRANCIS ◽  
J. KEESEE ◽  
J. LANG ◽  
G. SPARKS ◽  
G. SISSON
Keyword(s):  
Separated Flow ◽  
Aerodynamic Characteristics ◽  
Unsteady Separated Flow

scholarly journals Vortex Shedding from a Circular Cylinder with Spiral Fin

2008 ◽  
Vol 3 (6) ◽  
pp. 787-795 ◽  
Author(s):  
Hiromitsu HAMAKAWA ◽  
Keisuke NAKASHIMA ◽  
Tomohiro KUDO ◽  
Eiichi NISHIDA ◽  
Tohru FUKANO
Keyword(s):  
Circular Cylinder ◽  
Vortex Shedding

Vortex shedding from a circular cylinder in moderate-Reynolds-number shear flow

1980 ◽  
Vol 101 (4) ◽  
pp. 721-735 ◽  
Author(s):  
Masaru Kiya ◽  
Hisataka Tamura ◽  
Mikio Arie
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Shear Flow ◽  
Vortex Shedding ◽  
Transverse Velocity ◽  
Number Range ◽  
Uniform Shear ◽  
Reynolds Number Range ◽  
Moderate Reynolds Number ◽  
Shear Parameter

The frequency of vortex shedding from a circular cylinder in a uniform shear flow and the flow patterns around it were experimentally investigated. The Reynolds number Re, which was defined in terms of the cylinder diameter and the approaching velocity at its centre, ranged from 35 to 1500. The shear parameter, which is the transverse velocity gradient of the shear flow non-dimensionalized by the above two quantities, was varied from 0 to 0·25. The critical Reynolds number beyond which vortex shedding from the cylinder occurred was found to be higher than that for a uniform stream and increased approximately linearly with increasing shear parameter when it was larger than about 0·06. In the Reynolds-number range 43 < Re < 220, the vortex shedding disappeared for sufficiently large shear parameters. Moreover, in the Reynolds-number range 100 < Re < 1000, the Strouhal number increased as the shear parameter increased beyond about 0·1.

Application of RANS and LES to the Prediction of Flows in High Pressure Turbine Components

2011 ◽  
Author(s):  
Nicolas Gourdain ◽  
Laurent Y. M. Gicquel ◽  
Remy Fransen ◽  
Elena Collado ◽  
Tony Arts
Keyword(s):  
Heat Transfer ◽  
Vortex Shedding ◽  
Guide Vane ◽  
Unsteady Flows ◽  
Separated Flow ◽  
Heat Fluxes ◽  
Boundary Layer Transition ◽  
Wall Heat Transfer ◽  
Layer Transition ◽  
Turbine Guide Vane

This paper investigates the capability of numerical simulations to estimate unsteady flows and wall heat fluxes in turbine components with both structured and unstructured flow solvers. Different numerical approaches are assessed, from steady-state methods based on the Reynolds Averaged Navier-Stokes (RANS) equations to more sophisticated methods such as the Large Eddy Simulation (LES) technique. Three test cases are investigated: the vortex shedding induced by a turbine guide vane, the wall heat transfer in another turbine guide vane and a separated flow phenomenon in an internal turbine cooling channel. Steady flow simulations usually fail to predict the mean effects of unsteady flows (such as vortex shedding) and wall heat transfer, mainly because laminar-to turbulent transition and the inlet turbulent intensity are not correctly taken into account. Actually, only the LES (partially) succeeds to accurately estimate unsteady flows and wall heat fluxes in complex configurations. The results presented in this paper indicate that this method considerably improves the level of physical description (including boundary layer transition). However, the LES still requires developments and validations for such complex flows. This study also points out the dependency of results to parameters such as the freestream turbulence intensity. When feasible solutions obtained with both structured and unstructured flow solvers are compared to experimental data.

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