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Wind and Structures
  Volume 10, Number 6, November 2007 , pages 511-532
DOI: https://doi.org/10.12989/was.2007.10.6.511
 


Large eddy simulation of a square cylinder flow: Modelling of inflow turbulence
M. Tutar and I. Celik

 
Abstract
    The present study aims to generate turbulent inflow data to more accurately represent the turbulent flow around a square cylinder when the inflow turbulence level is significant. The modified random flow generation (RFG) technique in conjunction with a previously developed LES code is successfully adopted into a finite element based fluid flow solver to generate the required inflow turbulence boundary conditions for the three-dimensional (3-D) LES computations of transitional turbulent flow around a square cylinder at Reynolds number of 22,000. The near wall region is modelled without using wall approximate conditions and a wall damping coefficient is introduced into the calculation of sub-grid length scale in the boundary layer of the cylinder wall. The numerical results obtained from simulations are compared with each other and with the experimental data for different inflow turbulence boundary conditions in order to discuss the issues such as the synthetic inflow turbulence effects on the 3-D transitional flow behaviour in the near wake and the free shear layer, the basic mechanism by which stream turbulence interacts with the mean flow over the cylinder body and the prediction of integral flow parameters. The comparison among the LES results with and without inflow turbulence and the experimental data emphasizes that the turbulent inflow data generated by the present RFG technique for the LES computation can be a viable approach in accurately predicting the effects of inflow turbulence on the near wake turbulent flow characteristics around a bluff body.
 
Key Words
    computational methods; random flow generation (RFG) algorithm; turbulence; large eddy simulation (LES); square cylinder; inflow turbulence.
 
Address
M. Tutar; Mersin University, Department of Mechanical Engineering, Ciftlikkoy, 33343, Mersin, Turkey
I. Celik; West Virginia University, Department of Mechanical and Aerospace Engineering, Morgantown, WV 26506-6106, USA
 

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