A numerical analysis of vortex shedding within a confined channel flow

1999 ◽  
Vol 213 (5) ◽  
pp. 477-490 ◽  
Author(s):  
T. J. Scanlon ◽  
M. T. Stickland ◽  
A Oldroyd
Keyword(s):  
Numerical Analysis ◽  
Channel Flow ◽  
Vortex Shedding ◽  
Convective Transport ◽  
Fully Implicit ◽  
Order Scheme ◽  
Computational Fluid Dynamics Cfd ◽  
Vortex Shedding Frequency ◽  
Higher Order Scheme ◽  
Confined Channel

The numerical analysis of two-dimensional laminar vortex shedding from a rectangular cylinder within a confined channel flow is presented. This study, carried out using a computational fluid dynamics (CFD) code based on the SIMPLEST algorithm, considers the influence of numerical diffusion on the prediction of the vortex shedding frequency. The computational analysis compares the commonly used first-order accurate UPWIND scheme with the well-known third-order scheme QUICK and its derivative SMART, used for the discretization of convective transport. For the temporal differencing, a fully implicit scheme has been adopted. Plots of Strouhal number against Reynolds number suggest that the implementation of a higher-order scheme is beneficial for the accurate capture of the vortex shedding transient in unsteady flows of this nature.

The Reduction of False Diffusion in the Simulation of Vortex Shedding

1992 ◽  
Vol 206 (6) ◽  
pp. 399-406 ◽  
Author(s):  
C Carey ◽  
T J Scanlon ◽  
S M Fraser
Keyword(s):  
Laminar Flow ◽  
Channel Flow ◽  
Vortex Shedding ◽  
Computational Analysis ◽  
Bluff Body ◽  
Convective Transport ◽  
Two Dimensional ◽  
Transient Phenomenon ◽  
First Order ◽  
Confined Channel

The computational analysis of two-dimensional laminar vortex shedding from a rectangular bluff body in a confined channel flow is presented. In this analysis it is shown how the use of the conventional first-order hybrid-upwind convective differencing scheme provides an excellent example of the effects of multi-dimensional false diffusion. These effects are reduced substantially with the introduction of a new scheme, SU CCA (skew upwind corner convection algorithm), for the modelling of convective transport, resulting in the promotion of continuous vortex shedding. The introduction of the SVCCA scheme indicates that a complex transient phenomenon such as vortex shedding can be analysed using a modified first-order convection algorithm. The results also demonstrate the SVCCA scheme's ability to represent convective transport more accurately and hence help minimize the effects of multi-dimensional false diffusion in the numerical solution of the Navier-Slokes equation applied to laminar flow.

scholarly journals Study of Vortex-Shedding-Induced Vibration of a Flexible Splitter Plate Behind a Cylinder

2012 ◽  
Author(s):  
Jinmo Lee ◽  
Donghyun You
Keyword(s):  
Vortex Shedding ◽  
Splitter Plate ◽  
Flexible Plate ◽  
Stress Distributions ◽  
Computational Structural Dynamics ◽  
Computational Fluid Dynamics Cfd ◽  
Vortex Shedding Frequency ◽  
Shedding Frequency ◽  
Drag And Lift ◽  
Rear Stagnation Point

Integrated computational fluid dynamics (CFD) and computational structural dynamics (CSD) simulations of flow over a cylinder with a flexible splitter plate attached to the rear stagnation point, are performed. Flow over a cylinder produces vortex shedding, which causes unsteady pressure and shear stress distributions over a flexible splitter plate. As a result, the flexible splitter plate vibrates with distinct frequencies, which are different from the vortex-shedding frequency and natural frequencies of the plate. A systematic and detailed analysis of the effects of the flexible plate on fluid-structure dynamics and on the drag and lift of the cylinder, is presented.

The Influence of Boundary Layer Velocity Gradients and Bed Proximity on Vortex Shedding From Free Spanning Pipelines

1984 ◽  
Vol 106 (1) ◽  
pp. 70-78 ◽  
Author(s):  
A. J. Grass ◽  
P. W. J. Raven ◽  
R. J. Stuart ◽  
J. A. Bray
Keyword(s):  
Boundary Layer ◽  
Strouhal Number ◽  
Vortex Shedding ◽  
Combined Effects ◽  
Maximum Increase ◽  
Velocity Gradients ◽  
Large Velocity ◽  
Layer Velocity ◽  
Vortex Shedding Frequency ◽  
Shedding Frequency

The paper summarizes the results of a laboratory study of the separate and combined effects of bed proximity and large velocity gradients on the frequency of vortex shedding from pipeline spans immersed in the thick boundary layers of tidal currents. This investigation forms part of a wider project concerned with the assessment of span stability. The measurements show that in the case of both sheared and uniform approach flows, with and without velocity gradients, respectively, the Strouhal number defining the vortex shedding frequency progressively increases as the gap between the pipe base and the bed is reduced below two pipe diameters. The maximum increase in vortex shedding Strouhal number, recorded close to the bed in an approach flow with large velocity gradients, was of the order of 25 percent.

An Experimental Study on the Vertical Flow Past a Finite-Length Horizontal Cylinder at Low Reynolds Numbers

2014 ◽  
Vol 493 ◽  
pp. 68-73 ◽  
Author(s):  
Willy Stevanus ◽  
Yi Jiun Peter Lin
Keyword(s):  
Finite Length ◽  
Vortex Shedding ◽  
Vortex Formation ◽  
Reynolds Numbers ◽  
Horizontal Cylinder ◽  
Vortex Street ◽  
Vertical Flow ◽  
Low Reynolds Numbers ◽  
Vortex Shedding Frequency ◽  
Shedding Frequency

The research studies the characteristics of the vertical flow past a finite-length horizontal cylinder at low Reynolds numbers (ReD) from 250 to 1080. The experiments were performed in a vertical closed-loop water tunnel. Flow fields were observed by the particle tracer approach for flow visualization and measured by the Particle Image Velocimetry (P.I.V.) approach for velocity fields. The characteristics of vortex formation in the wake of the finite-length cylinder change at different regions from the tip to the base of it. Near the tip, a pair of vortices in the wake was observed and the size of the vortex increased as the observed section was away from the tip. Around a distance of 3 diameters of the cylinder from its tip, the vortex street in the wake was observed. The characteristics of vortex formation also change with increasing Reynolds numbers. At X/D = -3, a pair of vortices was observed in the wake for ReD = 250, but as the ReD increases the vortex street was observed at the same section. The vortex shedding frequency is analyzed by Fast Fourier Transform (FFT). Experimental results show that the downwash flow affects the vortex shedding frequency even to 5 diameters of the cylinder from its tip. The interaction between the downwash flow and the Von Kármán vortex street in the wake of the cylinder is presented in this paper.

A Parallel HOFD Scheme for Direct Numerical Simulation of Turbulent Magnetically Driven Flows

2001 ◽  
Author(s):  
X. Ai ◽  
B. Q. Li
Keyword(s):  
Numerical Simulation ◽  
Finite Difference ◽  
Direct Numerical Simulation ◽  
Turbulent Flows ◽  
Parallel Machines ◽  
Higher Order ◽  
Electrically Conducting ◽  
Wide Range ◽  
Order Scheme ◽  
Higher Order Scheme

Abstract Turbulent magnetically flows occur in a wide range of material processing systems involving electrically conducting melts. This paper presents a parallel higher order scheme for the direct numerical simulation of turbulent magnetically driven flows in induction channels. The numerical method is based on the higher order finite difference algorithm, which enjoys the spectral accuracy while minimizing the computational intensity. This, coupled with the parallel computing strategy, provides a very useful means to simulate turbulent flows. The higher order finite difference formulation of magnetically driven flow problems is described in this paper. The details of the parallel algorithm and its implementation for the simulations on parallel machines are discussed. The accuracy and numerical performance of the higher order finite difference scheme are assessed in comparison with the spectral method. The examples of turbulent magnetically driven flows in induction channels and pressure gradient driven flows in regular channels are given, and the computed results are compared with experimental measurements wherever possible.

Elastic particle deformation in rectangular channel flow as a measure of particle stiffness

Soft Matter ◽  
2018 ◽  
Vol 14 (2) ◽  
pp. 216-227 ◽  
Author(s):  
Margaret Y. Hwang ◽  
Seo Gyun Kim ◽  
Heon Sang Lee ◽  
Susan J. Muller
Keyword(s):  
Shear Modulus ◽  
Channel Flow ◽  
Rectangular Channel ◽  
Particle Deformation ◽  
Experimental Deformation ◽  
Soft Particles ◽  
Elastic Particle ◽  
Confined Channel

Experimental deformation of hydrogel soft particles in a confined channel is quantified and can be used to obtain shear modulus.

Vortex-Induced Vibration for Heat Transfer Enhancement

2014 ◽  
Author(s):  
Junxiang Shi ◽  
Steven R. Schafer ◽  
Chung-Lung (C. L. ) Chen
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Heat Transfer Enhancement ◽  
Natural Frequency ◽  
Vortex Shedding ◽  
Pressure Loss ◽  
Thermal Boundary Layer ◽  
Transfer Enhancement ◽  
Vortex Shedding Frequency ◽  
Shedding Frequency

A passive, self-agitating method which takes advantage of vortex-induced vibration (VIV) is presented to disrupt the thermal boundary layer and thereby enhance the convective heat transfer performance of a channel. A flexible cylinder is placed at centerline of a channel. The vortex shedding due to the presence of the cylinder generates a periodic lift force and the consequent vibration of the cylinder. The fluid-structure-interaction (FSI) due to the vibration strengthens the disruption of the thermal boundary layer by reinforcing vortex interaction with the walls, and improves the mixing process. This novel concept is demonstrated by a three-dimensional modeling study in different channels. The fluid dynamics and thermal performance are discussed in terms of the vortex dynamics, disruption of the thermal boundary layer, local and average Nusselt numbers (Nu), and pressure loss. At different conditions (Reynolds numbers, channel geometries, material properties), the channel with the VIV is seen to significantly increase the convective heat transfer coefficient. When the Reynolds number is 168, the channel with the VIV improves the average Nu by 234.8% and 51.4% in comparison with a clean channel and a channel with a stationary cylinder, respectively. The cylinder with the natural frequency close to the vortex shedding frequency is proved to have the maximum heat transfer enhancement. When the natural frequency is different from the vortex shedding frequency, the lower natural frequency shows a higher heat transfer rate and lower pressure loss than the larger one.

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