Triggering vortex shedding for flow past circular cylinder by acting on initial conditions: A numerical study

2014 ◽  
Vol 101 ◽  
pp. 194-207 ◽  
Author(s):  
Mouna Laroussi ◽  
Mohamed Djebbi ◽  
Mahmoud Moussa
Keyword(s):  
Circular Cylinder ◽  
Vortex Shedding ◽  
Initial Conditions ◽  
Numerical Study ◽  
Flow Past

Oscillatory flow past a circular cylinder in a rotating frame

1997 ◽  
Vol 345 ◽  
pp. 101-131
Author(s):  
M. D. KUNKA ◽  
M. R. FOSTER
Keyword(s):  
Circular Cylinder ◽  
Steady Flow ◽  
Stagnation Point ◽  
Oscillatory Flow ◽  
Numerical Solutions ◽  
Initial Conditions ◽  
Temporal Integration ◽  
Oncoming Flow ◽  
Flow Past ◽  
Rear Stagnation Point

Because of the importance of oscillatory components in the oncoming flow at certain oceanic topographic features, we investigate the oscillatory flow past a circular cylinder in an homogeneous rotating fluid. When the oncoming flow is non-reversing, and for relatively low-frequency oscillations, the modifications to the equivalent steady flow arise principally in the ‘quarter layer’ on the surface of the cylinder. An incipient-separation criterion is found as a limitation on the magnitude of the Rossby number, as in the steady-flow case. We present exact solutions for a number of asymptotic cases, at both large frequency and small nonlinearity. We also report numerical solutions of the nonlinear quarter-layer equation for a range of parameters, obtained by a temporal integration. Near the rear stagnation point of the cylinder, we find a generalized velocity ‘plateau’ similar to that of the steady-flow problem, in which all harmonics of the free-stream oscillation may be present. Further, we determine that, for certain initial conditions, the boundary-layer flow develops a finite-time singularity in the neighbourhood of the rear stagnation point.

A Combined Experimental and Numerical Study of Flow Past a Single Step Cylinder

2010 ◽  
Author(s):  
Chris R. Morton ◽  
Serhiy Yarusevych
Keyword(s):  
Vortex Shedding ◽  
Numerical Study ◽  
Experimental Tests ◽  
Numerical Approach ◽  
Single Step ◽  
Wake Flow ◽  
Cylinder Wake ◽  
Flow Topology ◽  
Single Vortex ◽  
Flow Past

The current study investigates flow past a step cylinder for ReD = 1050 and D/d = 2 using both experimental and numerical methods. The focus of the study is on the vortex shedding and vortex interactions occurring in the step cylinder wake. Flow visualization with hydrogen bubble technique and planar Laser Induced Fluorescence has shown that three distinct spanwise vortex cells form: a single vortex shedding cell in the wake of the small cylinder and two vortex shedding cells in the wake of the large cylinder. Vortex connections form between the spanwise vortices in these cells downstream of the step, and vortex dislocations occur at cell boundaries. Complementary to the experimental tests, an LES-RANS hybrid numerical simulation is used to model the flow development. A comparison of the experimental and numerical results indicates that the numerical approach adequately models vortex dynamics in the wake of a step cylinder and, thus, may be used to analyze time dependent, three-dimensional flow topology which is difficult to characterize quantitatively using experimental methods.

A Numerical Simulation of Vortex Induced Vibration on a Elastically Supported Circular Rigid Cylinder at Moderate Reynolds Numbers

2008 ◽  
Author(s):  
Jean-Franc¸ois Sigrist ◽  
Cyrille Allery ◽  
Claudine Beghein
Keyword(s):  
Numerical Simulation ◽  
Fluid Flow ◽  
Circular Cylinder ◽  
Finite Volume ◽  
Vortex Shedding ◽  
Numerical Study ◽  
Reynolds Numbers ◽  
Forced Oscillations ◽  
Vortex Induced Vibration ◽  
Elastically Supported

The present paper is the sequel of a previously published study which is concerned with the numerical simulation of vortex-induced-vibration (VIV) on an elastically supported rigid circular cylinder in a fluid cross-flow (A. Placzek, J.F. Sigrist, A. Hamdouni; Numerical Simulation of Vortex Shedding Past a Circular Cylinder at Low Reynolds Number with Finite Volume Technique. Part I: Forced Oscillations, Part II: Flow Induced Vibrations; Pressure Vessel and Piping, San Antonio, 22–26 July 2007). Such a problem has been thoroughly studied over the past years, both from the experimental and numerical points of view, because of its theoretical and practical interest in the understanding on flow-induced vibration problems. In this context, the present paper aims at exposing a numerical study based on a fully coupled fluid-structure simulation. The numerical technique is based on a finite volume discretisation of the fluid flow equations together with i) a re-meshing algorithm to account for the cylinder motion ii) a projection subroutine to compute the forces induced by the fluid on the cylinder and iii) a coupling procedure to describe the energy exchanges between the fluid flow and solid motion. The study is restricted to moderate Reynolds numbers (Re∼2.000–10.000) and is performed with an industrial CFD code. Numerical results are compared with existing literature on the subject, both in terms of cylinder amplitude motion and fluid vortex shedding modes. Ongoing numerical studies with different numerical techniques, such as ROM (Reduced Order Models)-based methods, will complete the approach and will be published in next PVP conference. These numerical simulations are proposed for code validation purposes prior to industrial applications in tube bundle configuration.

Numerical study of vortex shedding in viscoelastic flow past an unconfined square cylinder

2015 ◽  
Vol 27 (3) ◽  
pp. 213-225 ◽  
Author(s):  
Mahmood Norouzi ◽  
Seyed Rasoul Varedi ◽  
Mahdi Zamani
Keyword(s):  
Vortex Shedding ◽  
Numerical Study ◽  
Viscoelastic Flow ◽  
Square Cylinder ◽  
Flow Past

Influence of slip on the flow past superhydrophobic circular cylinders

2011 ◽  
Vol 680 ◽  
pp. 459-476 ◽  
Author(s):  
PRANESH MURALIDHAR ◽  
NANGELIE FERRER ◽  
ROBERT DANIELLO ◽  
JONATHAN P. ROTHSTEIN
Keyword(s):  
Circular Cylinder ◽  
Vortex Shedding ◽  
Flow Direction ◽  
Superhydrophobic Surfaces ◽  
Separation Point ◽  
Circular Cylinders ◽  
Recirculation Region ◽  
Small Scale ◽  
Flow Past ◽  
Shedding Frequency

Superhydrophobic surfaces have been shown to produce significant drag reduction for both laminar and turbulent flows of water through large- and small-scale channels. In this paper, a series of experiments were performed which investigated the effect of superhydrophobic-induced slip on the flow past a circular cylinder. In these experiments, circular cylinders were coated with a series of superhydrophobic surfaces fabricated from polydimethylsiloxane with well-defined micron-sized patterns of surface roughness. The presence of the superhydrophobic surface was found to have a significant effect on the vortex shedding dynamics in the wake of the circular cylinder. When compared to a smooth, no-slip cylinder, cylinders coated with superhydrophobic surfaces were found to delay the onset of vortex shedding and increase the length of the recirculation region in the wake of the cylinder. For superhydrophobic surfaces with ridges aligned in the flow direction, the separation point was found to move further upstream towards the front stagnation point of the cylinder and the vortex shedding frequency was found to increase. For superhydrophobic surfaces with ridges running normal to the flow direction, the separation point and shedding frequency trends were reversed. Thus, in this paper we demonstrate that vortex shedding dynamics is very sensitive to changes of feature spacing, size and orientation along superhydrophobic surfaces.

scholarly journals Some Modelling Issues on Trailing Edge Vortex Shedding

1999 ◽  
Author(s):  
Wei Ning ◽  
Li He
Keyword(s):  
Circular Cylinder ◽  
Vortex Shedding ◽  
Stokes Equations ◽  
Numerical Study ◽  
Independent Solution ◽  
Navier Stokes ◽  
Trailing Edge ◽  
Navier Stokes Equations ◽  
Averaged Equations ◽  
Edge Vortex

A numerical study has been carried out to investigate modelling issues on trailing edge vortex shedding. The vortex shedding from a circular cylinder and a VKI turbine blade is calculated using a 2-D unsteady multi-block Navier-Stokes solver. The unsteady stresses are calculated from the unsteady solutions. The distributions of the unsteady stresses are analysed and compared for the cylinder case and the cascade case, respectively. The time-averaged equations are then solved and the effectiveness of the “unsteady stresses” in suppressing trailing edge vortex shedding is checked. Finally, the time-independent solution produced by solving the time-averaged equations is compared with the time-averaged solution obtained by integrating the unsteady solutions. The numerical results have demonstrated that a time-independent vortex shedding solution can be achieved by solving the Navier-Stokes equations with the unsteady stresses and the time-averaged effects of the vortex shedding can be included.

scholarly journals Numerical Study on Viscous Shear Flow past a Circular Cylinder

1980 ◽  
Vol 23 (186) ◽  
pp. 1952-1958 ◽  
Author(s):  
Hisataka TAMURA ◽  
Masaru KIYA ◽  
Mikio ARIE
Keyword(s):  
Circular Cylinder ◽  
Shear Flow ◽  
Numerical Study ◽  
Flow Past ◽  
Viscous Shear ◽  
Viscous Shear Flow
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