Staggered circular cylinders immersed in a uniform planar shear flow

2003 ◽  
Vol 18 (5) ◽  
pp. 613-633 ◽  
Author(s):  
O.O. Akosile ◽  
D. Sumner
Keyword(s):  
Shear Flow ◽  
Circular Cylinders ◽  
Planar Shear

Dynamic responses and flow-induced vibration mechanism of three tandem circular cylinders in planar shear flow

2020 ◽  
Vol 199 ◽  
pp. 107022
Author(s):  
Jiahuang Tu ◽  
Xiaoling Tan ◽  
Xuhui Deng ◽  
Zhaolong Han ◽  
Min Zhang ◽  
...  
Keyword(s):  
Shear Flow ◽  
Dynamic Responses ◽  
Circular Cylinders ◽  
Flow Induced Vibration ◽  
Planar Shear ◽  
Vibration Mechanism

An Experimental Investigation of Staggered Circular Cylinders in a Uniform Planar Shear Flow

2002 ◽  
Author(s):  
O. O. Akosile ◽  
D. Sumner
Keyword(s):  
Shear Flow ◽  
Strouhal Number ◽  
Vortex Shedding ◽  
Bluff Body ◽  
Incidence Angle ◽  
Lift Coefficient ◽  
Circular Cylinders ◽  
Aerodynamic Forces ◽  
Planar Shear ◽  
Critical Incidence

Two circular cylinders of equal diameter, arranged in staggered configurations of P/D = 1.125 and 1.25, were immersed in a uniform planar shear flow, at Re = 5.0×104 and a dimensionless shear parameter of K = 0.05. The mean aerodynamic forces and the vortex shedding frequencies were measured for the upstream and downstream cylinders at each P/D. Under uniform, no-shear flow conditions, K = 0, the flow field of the cylinder group is similar to a single bluff body. As the incidence angle is varied from α = 0° to 90°, the forces on each cylinder undergo discontinuous changes, or attain local minimum or maximum values, at several critical incidence angles. At small α, the Strouhal number is greater than that of a single, isolated circular cylinder, whereas at high α the Strouhal number is lower than the single-cylinder value. The effects of shear, K = 0.05, on the aerodynamic forces were different depending on whether the downstream cylinder was situated at a higher or lower centreline velocity compared to the upstream cylinder. The planar shear flow had its greatest influence when the cylinders were in a nearly side-by-side arrangement. This indicated that the effect of shear was mostly on the flow through the gap between the cylinders. The lift coefficient data were mostly unchanged by the shear flow, the drag coefficient data were lowered, and there were shifts in the critical incidence angles. The influence of shear on vortex shedding was less pronounced, but there was a small reduction in Strouhal number compared to the no-shear case.

Simulation of Planar Shear Flow Passing Two Equal-Sized Circular Cylinders in Tandem Arrangement

2011 ◽  
Author(s):  
Keivan Fallah ◽  
Abas Ali Fardad ◽  
Ehsan Fattahi ◽  
Nima Sedaghati Zadeh ◽  
Muhammed Hasan Aslan ◽  
...  
Keyword(s):  
Shear Flow ◽  
Circular Cylinders ◽  
Tandem Arrangement ◽  
Planar Shear

An Energy-Based Similarity Subgrid-Scale Model in Two-Dimensional Planar Shear Flow

2013 ◽  
Vol 694-697 ◽  
pp. 594-600
Author(s):  
Yu Xuan Zhang ◽  
Song Ping Wu
Keyword(s):  
Shear Flow ◽  
Scale Model ◽  
Two Dimensional ◽  
Subgrid Scale ◽  
Planar Shear ◽  
New Type ◽  
Subgrid Scale Model ◽  
Layer Flow ◽  
Refined Grid ◽  
Dissipative Scale

A new type of similarity subgrid-scale (SGS) model which based on energy and dissipative scale isotropy assumption is presented. This model combines the advantages of traditional Smagorinsky SGS model with similarity SGS model. And a two-dimensional shear layer flow is simulated using refined grid result as a standard and comparing witch LES method including multiple SGS models. The results indicate that the result of SIM model much approximates to refined grid result than other SGS models.

On a Circular Cylinder in a Uniform Planar Shear Flow at Subcritical Reynolds Number

2002 ◽  
Author(s):  
D. Sumner ◽  
O. O. Akosile
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Shear Flow ◽  
Lift Force ◽  
Experimental Studies ◽  
Reynolds Numbers ◽  
Low Velocity ◽  
Static Pressure Distribution ◽  
Planar Shear ◽  
The Mean

An experimental investigation was conducted of a circular cylinder immersed in a uniform planar shear flow, where the approach velocity varies across the diameter of the cylinder. The study was motivated by some apparent discrepancies between numerical and experimental studies of the flow, and the general lack of experimental data, particularly in the subcritical Reynolds number regime. Of interest was the direction and origin of the steady mean lift force experienced by the cylinder, which has been the subject of contradictory results in the literature, and for which measurements have rarely been reported. The circular cylinder was tested at Reynolds numbers from Re = 4.0×104 − 9.0×104, and the dimensionless shear parameter ranged from K = 0.02 − 0.07, which corresponded to a flow with low to moderate shear. The results showed that low to moderate shear has no appreciable influence on the Strouhal number, but has the effect of lowering the mean drag coefficient. The circular cylinder develops a small steady mean lift force directed towards the low-velocity side, which is attributed to an asymmetric mean static pressure distribution on its surface. The reduction in the mean drag force, however, cannot be attributed solely to this asymmetry.

scholarly journals Universal continuous transition to turbulence in a planar shear flow

2017 ◽  
Vol 824 ◽  
Author(s):  
Matthew Chantry ◽  
Laurette S. Tuckerman ◽  
Dwight Barkley
Keyword(s):  
Shear Flow ◽  
Universality Class ◽  
Transition To Turbulence ◽  
Free Boundaries ◽  
Turbulent Structures ◽  
Continuous Transition ◽  
Normal Representation ◽  
Onset Of Turbulence ◽  
Planar Shear ◽  
Order Of Magnitude

We examine the onset of turbulence in Waleffe flow – the planar shear flow between stress-free boundaries driven by a sinusoidal body force. By truncating the wall-normal representation to four modes, we are able to simulate system sizes an order of magnitude larger than any previously simulated, and thereby to attack the question of universality for a planar shear flow. We demonstrate that the equilibrium turbulence fraction increases continuously from zero above a critical Reynolds number and that statistics of the turbulent structures exhibit the power-law scalings of the (2 + 1)-D directed-percolation universality class.

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