Numerical Simulations of Turbulent Flow Over Two Surface-Mounted Tandem Square Cylinders

2017 ◽  
Author(s):  
Yukun Dai ◽  
Hong Wang ◽  
Cai Tian
Keyword(s):  
Turbulent Flow ◽  
Numerical Simulations ◽  
Wake Flow ◽  
Navier Stokes ◽  
Square Cylinder ◽  
Wake Effect ◽  
Simple Method ◽  
Square Cylinders ◽  
Tandem Square Cylinders ◽  
Turbulence Effect

Numerical simulations of wake flow generated by a surface-mounted square cylinder over a subsequent square cylinder are presented for incompressible low-Re turbulent flow. The behaviors of the square cylinder in the wake flow are investigated. A developed numerical method — Semi-Implicit Method for Pressure-Linked Equations (SIMPLE) is adopted to solve the governing equations in steady state. Turbulence effect is modelled by Reynolds Averaged Navier Stokes (RANS) equations with a standard k-ω turbulence model. The k-ω SIMPLE method is validated by comparison with experimental data. The results show that in wake flow, the square cylinder produces a much weaker wake effect and is subjected to an inverse drag force.

scholarly journals A Numerical Investigation of Turbulent Flow Over Single and Tandem Square Cylinders

2021 ◽  
Vol 40 (4) ◽  
pp. 724-746
Author(s):  
Mahrukh Mahrukh ◽  
Usman Allauddin ◽  
Mohammed Ehteshamul Haque ◽  
Naseem Uddin ◽  
Ahmed Hussain
Keyword(s):  
Three Dimensional ◽  
Navier Stokes ◽  
Stream Velocity ◽  
Shear Stresses ◽  
Square Cylinder ◽  
Tandem Arrangement ◽  
Square Cylinders ◽  
Contour Plots ◽  
Tandem Square Cylinders ◽  
Lift And Drag

This paper presents the three-dimensional flow investigations over the square cylinders placed in the tandem arrangement. Two different flow configurations were investigated in detail; one comprising of a single square cylinder and the other comprising of three square cylinders placed in a tandem arrangement with the spacing of six times the width (w) of each square cylinder. The Reynolds number based on the width of the square cylinder (w) and free stream velocity (Uo) is 22,000. The problem was solved numerically using an Unsteady Reynolds-Averaged Navier-Stokes (URANS) based model and Large Eddy Simulation (LES) based model. Strouhal Number, lift, and drag coefficients were computed for each configuration. By comparing both the models using contour plots of pressure, velocity and vorticity it is found that the LES model is more accurate to capture the turbulence around single and tandem square cylinders. In the tandem arrangement, complex periodic vortex shedding was observed in the wake of each square cylinder. The production of turbulent kinetic energy was also investigated to understand the roles of stresses during flow over the cylinders. The analysis showed that the production of turbulence by normal stresses is higher than that of shear stresses. Furthermore, it was observed that the flow over the first cylinder arranged in tandem is quite identical to that of the single square cylinder. Moreover, the upstream cylinder experienced a higher lift in comparison to the downstream cylinders.

scholarly journals Prediction of Turbulent Flow Around a Square Cylinder With Rounded Corners

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
S. S. Dai ◽  
B. A. Younis ◽  
H. Y. Zhang
Keyword(s):  
Turbulent Flow ◽  
Vortex Shedding ◽  
Turbulence Closure ◽  
Navier Stokes ◽  
Square Cylinder ◽  
Mean Flow ◽  
Drag Forces ◽  
Turbulence Closures ◽  
High Reynolds ◽  
Lift And Drag

Predictions are reported of the two-dimensional turbulent flow around a square cylinder with rounded corners at high Reynolds numbers. The effects of rounded corners have proved difficult to predict with conventional turbulence closures, and hence, the adoption in this study of a two-equation closure that has been specifically adapted to account for the interactions between the organized mean-flow motions due to vortex shedding and the random motions due to turbulence. The computations were performed using openfoam and were validated against the data from flows past cylinders with sharp corners. For the case of rounded corners, only the modified turbulence closure succeeded in capturing the consequences of the delayed flow separation manifested mainly in the reduction of the magnitude of the lift and drag forces relative to the sharp-edged case. These and other results presented here argue in favor of the use of the computationally more efficient unsteady Reynolds-averaged Navier-Stokes approach to this important class of flows provided that the effects of vortex shedding are properly accounted for in the turbulence closure.

Numerical Turbulent Analysis for Flow Around a Square Cylinder Using the Finite Element Method

2003 ◽  
Author(s):  
Shinichiro Miura ◽  
Kazuhiko Kakuda
Keyword(s):  
Finite Element ◽  
Flow Field ◽  
Turbulent Flow ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Square Cylinder ◽  
Weak Formulation ◽  
Finite Element Scheme ◽  
Navier Stokes Equations ◽  
Element Scheme

A finite element scheme based on the Petrov-Galerkin weak formulation using exponential weighting functions for solving accurately, and in a stable manner, the flow field of an incompressible viscous fluid has been proposed in our previous works. In this paper, we present the Petrov-Galerkin finite element scheme for turbulent flow field. The incompressible Navier-Stokes equations are numerically integrated in time by using a fractional step strategy with second-order accurate Adams-Bashforth explicit differencing for both convection and diffusion terms. Numerical results obtained herein are compared through turbulent flow around a square cylinder at Re = 22,000 with the experimental data and other existing numerical ones.

A smoke visualization study of the flow over a square cylinder at incidence and tandem square cylinders

2015 ◽  
Vol 18 (4) ◽  
pp. 687-703 ◽  
Author(s):  
A. Sohankar ◽  
S. Mohagheghian ◽  
A. A. Dehghan ◽  
M. Dehghan Manshadi
Keyword(s):  
Square Cylinder ◽  
Smoke Visualization ◽  
Square Cylinders ◽  
Tandem Square Cylinders

Study of turbulent flow past a square cylinder using partially-averaged Navier–Stokes method in OpenFOAM

2020 ◽  
Vol 234 (14) ◽  
pp. 2821-2832 ◽  
Author(s):  
Arnab Chakraborty ◽  
HV Warrior
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Turbulent Flow ◽  
Turbulent Flows ◽  
Normal Direction ◽  
Navier Stokes ◽  
Square Cylinder ◽  
Mean Velocity ◽  
Wide Range ◽  
Reynolds Averaged Navier Stokes

The present paper reports numerical simulation of turbulent flow over a square cylinder using a novel scale resolving computational fluid dynamics technique named Partially-Averaged Navier–Stokes (PANS), which bridges Reynolds-Averaged Navier–Stokes (RANS) with Direct Numerical Simulation (DNS) in a seamless manner. All stream-wise and wall normal mean velocity components, turbulent stresses behavior have been computed along the flow (streamwise) as well as in transverse (wall normal) direction. The measurement locations are chosen based on the previous studies so that results could be compared. However, the Reynolds number ( Re) of the flow is maintained at 21,400 and K– ω turbulence model is considered for the present case. All the computations are performed in OpenFOAM framework using a finite volume solver. Additionally, turbulent kinetic energy variations are presented over a wide range of measurement planes in order to explain the energy transfer process in highly unsteady turbulent flow field. The fluctuating root mean square velocities in the streamwise as well as in the wall normal direction have been discussed in the present work. It has been found that Partially-Averaged Navier–Stokes (PANS) model is capable of capturing the properties of highly unsteady turbulent flows and gives better results than Reynolds-Averaged Navier–Stokes (RANS). The results obtained using Partially-Averaged Navier–Stokes (PANS) are quite comparable with Large Eddy Simulation (LES) and Direct Numerical Simulation (DNS) data available in literature. The partially-averaged Navier–Stokes results are compared with our simulated Reynolds-Averaged Navier–Stokes (RANS) results, available experimental as well as numerical results in literature and it is found to be good in agreement.

scholarly journals New insights into numerical simulations of flow around two tandem square cylinders

AIP Advances ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 045315
Author(s):  
Qingxiang Shui ◽  
Cuie Duan ◽  
Daguo Wang ◽  
Zhaolin Gu
Keyword(s):  
Numerical Simulations ◽  
Square Cylinders ◽  
Tandem Square Cylinders
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