Numerical Prediction of Turbulent Wakes Behind a Square Cylinder

1998 ◽  
Vol 14 (1) ◽  
pp. 23-29
Author(s):  
Robert R. Hwang ◽  
Sheng-Yuh Jaw
Keyword(s):  
Stokes Equations ◽  
Numerical Study ◽  
Navier Stokes ◽  
Wall Region ◽  
Square Cylinder ◽  
Mean Velocity ◽  
Navier Stokes Equations ◽  
Turbulent Vortex Shedding ◽  
Model Equations ◽  
Good Agreement

ABSTRACTThis paper presents a numerical study on turbulent vortex shedding flows past a square cylinder. The 2D unsteady periodic shedding motion was resolved in the calculation and the superimposed turbulent fluctuations were simulated with a second-order Reynolds-stress closure model. The calculations were carried out by solving numerically the fully elliptic ensemble-averaged Navier-Stokes equations coupled with the turbulence model equations together with the two-layer approach in the treatment of the near-wall region. The performance of the computations was evaluated by comparing the numerical results with data from available experiments. Results indicate that the present study gives good agreement in the shedding frequency and mean drag as well as in some phase profiles of the mean velocity.

A Numerical Study of Vortex Shedding From a Square Cylinder With Ground Effect

1997 ◽  
Vol 119 (3) ◽  
pp. 512-518 ◽  
Author(s):  
Robert R. Hwang ◽  
Chia-Chi Yao
Keyword(s):  
Vortex Shedding ◽  
Stokes Equations ◽  
Numerical Study ◽  
Subsequent Development ◽  
Ground Effect ◽  
Navier Stokes ◽  
Square Cylinder ◽  
Navier Stokes Equations ◽  
Layer Flow ◽  
Volume Method

A numerical study has been conducted to investigate the behavior of the vortical wake created by a square cylinder placed in a laminar boundary-layer flow. The calculations are performed by solving the unsteady 2D Navier-Stokes equations with a finite-volume method. The Reynolds-number regime investigated is from 500 to 1500. Another parameter that is varied is the distance of the cylinder from the wall. The initial and subsequent development of the vortex shedding phenomenon are investigated. The presence of the wall is found to have strong effects on the properties of these vortices, as well as lift, drag, and Strouhal number.

Vortex Shedding From a Square Cylinder With Ground Effect

2003 ◽  
Author(s):  
S. Bhattacharyya ◽  
D. K. Maiti
Keyword(s):  
Reynolds Number ◽  
Vortex Shedding ◽  
Stokes Equations ◽  
Numerical Study ◽  
Ground Effect ◽  
Staggered Grid ◽  
Navier Stokes ◽  
Square Cylinder ◽  
Navier Stokes Equations ◽  
Cylinder Length

Numerical study on the wake behind a square cylinder placed parallel to a wall has been made. Flow has been investigated in the laminar Reynolds number (based on the cylinder length) range. We have studied the flow field for different values of the non-dimensional gap length between cylinder and the wall. The case when the cylinder is placed on the wall has also been considered. The governing unsteady Navier-Stokes equations are discretised through the finite volume method on staggered grid system. A SIMPLER type of algorithm has been used to compute the discretised equations iteratively. Vortex shedding has been found to be influenced by the wall. Vortex shedding suppression occurs beyond a critical value of the gap length. Due to the shear, the drag experienced by the cylinder is found to increase with the reduction of gap length. The flow is found to be steady when the cylinder is placed on the wall at a range of Reynolds number.

A Numerical Study of Unsteady Laminar Forced Convection From a Circular Cylinder

1976 ◽  
Vol 98 (2) ◽  
pp. 303-307 ◽  
Author(s):  
P. C. Jain ◽  
B. S. Goel
Keyword(s):  
Nusselt Number ◽  
Circular Cylinder ◽  
Forced Convection ◽  
Stokes Equations ◽  
Numerical Study ◽  
Reynolds Numbers ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Laminar Forced Convection ◽  
Good Agreement

A numerical investigation of an unsteady laminar forced convection from a circular cylinder is presented. The Navier-Stokes equations and the energy equation for an unsteady incompressible fluid flow are solved by the finite difference method. The results are obtained at Reynolds numbers 100 and 200. The temperature field around the cylinder is obtained throughout the region of computation and is shown by isotherms at different times. The variations of the local Nusselt number around the cylinder at different times are computed and shown by graphs. The mean Nusselt number and the Strouhal number are also calculated. The computed results are compared with the other available experimental and theoretical results and are found to be in good agreement with them.

Simulation of Unsteady Flow Around a Cylinder

2015 ◽  
Vol 3 (2) ◽  
pp. 28-49
Author(s):  
Ridha Alwan Ahmed
Keyword(s):  
Stokes Equations ◽  
Lift Coefficient ◽  
Reynolds Numbers ◽  
Mean Value ◽  
Navier Stokes ◽  
Cylinder Surface ◽  
Navier Stokes Equations ◽  
Flow Around A Cylinder ◽  
Numerical Grid ◽  
Good Agreement

       In this paper, the phenomena of vortex shedding from the circular cylinder surface has been studied at several Reynolds Numbers (40≤Re≤ 300).The 2D, unsteady, incompressible, Laminar flow, continuity and Navier Stokes equations have been solved numerically by using CFD Package FLUENT. In this package PISO algorithm is used in the pressure-velocity coupling.        The numerical grid is generated by using Gambit program. The velocity and pressure fields are obtained upstream and downstream of the cylinder at each time and it is also calculated the mean value of drag coefficient and value of lift coefficient .The results showed that the flow is strongly unsteady and unsymmetrical at Re>60. The results have been compared with the available experiments and a good agreement has been found between them

Numerical Modeling of Evolution of Boundary Between Incompressible Gas and Liquid in Two-Dimensional Region

2006 ◽  
Vol 4 ◽  
pp. 224-236
Author(s):  
A.S. Topolnikov
Keyword(s):  
Numerical Modeling ◽  
Interphase Boundary ◽  
Incompressible Liquid ◽  
Stokes Equations ◽  
Numerical Code ◽  
Navier Stokes ◽  
Two Phase ◽  
Navier Stokes Equations ◽  
Incompressible Media ◽  
Good Agreement

The paper is devoted to numerical modeling of Navier–Stokes equations for incompressible media in the case, when there exist gas and liquid inside the rectangular calculation region, which are separated by interphase boundary. The set of equations for incompressible liquid accounting for viscous, gravitational and surface (capillary) forces is solved by finite-difference scheme on the spaced grid, for description of interphase boundary the ideology of Level Set Method is used. By developed numerical code the set of hydrodynamic problems is solved, which describe the motion of two-phase incompressible media with interphase boundary. As a result of numerical simulation the solutions are obtained, which are in good agreement with existing analytical and experimental solutions.

scholarly journals Dynamics of Single Droplet Splashing on Liquid Film by Coupling FVM with VOF

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 841
Author(s):  
Yuzhen Jin ◽  
Huang Zhou ◽  
Linhang Zhu ◽  
Zeqing Li
Keyword(s):  
Liquid Film ◽  
Weber Number ◽  
Stokes Equations ◽  
Numerical Study ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Single Droplet ◽  
Navier Stokes Equations ◽  
Volume Method ◽  
The Relationship

A three-dimensional numerical study of a single droplet splashing vertically on a liquid film is presented. The numerical method is based on the finite volume method (FVM) of Navier–Stokes equations coupled with the volume of fluid (VOF) method, and the adaptive local mesh refinement technology is adopted. It enables the liquid–gas interface to be tracked more accurately, and to be less computationally expensive. The relationship between the diameter of the free rim, the height of the crown with different numbers of collision Weber, and the thickness of the liquid film is explored. The results indicate that the crown height increases as the Weber number increases, and the diameter of the crown rim is inversely proportional to the collision Weber number. It can also be concluded that the dimensionless height of the crown decreases with the increase in the thickness of the dimensionless liquid film, which has little effect on the diameter of the crown rim during its growth.

On the Flow Fields of Inertial Impactors

1974 ◽  
Vol 96 (4) ◽  
pp. 394-400 ◽  
Author(s):  
V. A. Marple ◽  
B. Y. H. Liu ◽  
K. T. Whitby
Keyword(s):  
Flow Field ◽  
Stokes Equations ◽  
Relaxation Method ◽  
Water Model ◽  
Navier Stokes ◽  
Visualization Technique ◽  
Navier Stokes Equations ◽  
Theoretical Results ◽  
Plate Distance ◽  
Good Agreement

The flow field in an inertial impactor was studied experimentally with a water model by means of a flow visualization technique. The influence of such parameters as Reynolds number and jet-to-plate distance on the flow field was determined. The Navier-Stokes equations describing the laminar flow field in the impactor were solved numerically by means of a finite difference relaxation method. The theoretical results were found to be in good agreement with the empirical observations made with the water model.

A numerical study of the interaction between unsteay free-stream disturbances and localized variations in surface geometry

1989 ◽  
Vol 209 ◽  
pp. 285-308 ◽  
Author(s):  
R. J. Bodonyi ◽  
W. J. C. Welch ◽  
P. W. Duck ◽  
M. Tadjfar
Keyword(s):  
Numerical Solutions ◽  
Free Stream ◽  
Stokes Equations ◽  
Numerical Study ◽  
Navier Stokes ◽  
Surface Geometry ◽  
Navier Stokes Equations ◽  
S Waves ◽  
Tollmien Schlichting

A numerical study of the generation of Tollmien-Schlichting (T–S) waves due to the interaction between a small free-stream disturbance and a small localized variation of the surface geometry has been carried out using both finite–difference and spectral methods. The nonlinear steady flow is of the viscous–inviscid interactive type while the unsteady disturbed flow is assumed to be governed by the Navier–Stokes equations linearized about this flow. Numerical solutions illustrate the growth or decay of the T–S waves generated by the interaction between the free-stream disturbance and the surface distortion, depending on the value of the scaled Strouhal number. An important result of this receptivity problem is the numerical determination of the amplitude of the T–S waves.

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