Evaluation of k-ε Reynolds stress modeling in an idealized urban canyon using LES

Abstract In this study, a large-eddy simulation (LES) was conducted to investigate the validity of the modeling of Reynolds stress in standard k-e model (k-e model) for urban canyon flow. It was confirmed that the LES was more reliable than the k-e model for urban canyon flow, through a comparison of experimental results. The k-e model failed to reproduce the spatial distribution of the mean velocity within the urban canyon. It underestimated the absolute value of Reynolds stress and eddy viscosity coefficient νt, when compared to the LES. On the leeward side of the urban canyon, νt obtained by the LES was negative and the counter gradient diffusion was seen to occur. The budget of transport equation was analyzed using the results of the LES. At the top of the urban canyon and within it, the convection and diffusion terms showed an increase when compared to the production and pressure strain correlation terms. The gradient diffusion approximation of was not valid because the local equilibrium of transport equation was not correct. It was found necessary to incorporate the effect of the convection and diffusion terms in the modeling of for urban canyon flow.

[1]  S. Murakami,et al.  COMPARISON OF VARIOUS TURBULENCE MODELS APPLIED TO A BLUFF BODY , 1993 .

[2]  S. Murakami,et al.  Wind tunnel experiments on how thermal stratification affects flow in and above urban street canyons , 2000 .

[3]  B. Blocken,et al.  Large-Eddy Simulation of pollutant dispersion around a cubical building: analysis of the turbulent mass transport mechanism by unsteady concentration and velocity statistics. , 2012, Environmental pollution.

[4]  Ryozo Ooka,et al.  CFD analysis of wind climate from human scale to urban scale , 1999 .

[5]  W. Rodi.  Comparison of LES and RANS calculations of the flow around bluff bodies , 1997 .

[6]  Zheng-Tong Xie,et al.  LES and RANS for Turbulent Flow over Arrays of Wall-Mounted Obstacles , 2006 .

[7]  A. Martilli,et al.  Comparison Between Large-Eddy Simulation and Reynolds-Averaged Navier–Stokes Computations for the MUST Field Experiment. Part II: Effects of Incident Wind Angle Deviation on the Mean Flow and Plume Dispersion , 2010 .

[8]  Y. Nagano,et al.  Nonlinear two-equation model taking into account the wall-limiting behavior and redistribution of stress components , 2004 .

[9]  B. Launder,et al.  Progress in the development of a Reynolds-stress turbulence closure , 1975, Journal of Fluid Mechanics.

[10]  Yoshihide Tominaga,et al.  CFD Simulation of Near-Field Pollutant Dispersion in the Urban Environment: A Review of Current Modeling Techniques , 2013 .

[11]  Jörg Franke,et al.  Recommendations of the COST action C14 on the use of CFD in predicting pedestrian wind environment , 2006 .

[12]  Francis H. Harlow,et al.  Transport Equations in Turbulence , 1970 .

[13]  Theodore Stathopoulos,et al.  Computational wind engineering: Past achievements and future challenges , 1997 .

[14]  Bert Blocken,et al.  Near-field pollutant dispersion in an actual urban area: Analysis of the mass transport mechanism by high-resolution Large Eddy Simulations , 2015 .

[15]  S. Orszag,et al.  Development of turbulence models for shear flows by a double expansion technique , 1992 .

[16]  Kit Ming Lam,et al.  Recent progress in CFD modelling of wind field and pollutant transport in street canyons , 2006 .

[17]  B. Launder,et al.  The numerical computation of turbulent flows , 1990 .

[18]  Yoshihide Tominaga,et al.  AIJ guidelines for practical applications of CFD to pedestrian wind environment around buildings , 2008 .

[19]  Ken-ichi Abe,et al.  Towards the development of a Reynolds-averaged algebraic turbulent scalar-flux model , 2001 .

[20]  N. Kasagi,et al.  DIRECT NUMERICAL SIMULATION OF COMBINED FORCED AND NATURAL TURBULENT CONVECTION IN A ROTATING PLANE CHANNEL , 1996 .

[21]  Christopher Baker,et al.  Large‐eddy simulation of turbulent flow in a street canyon , 2004 .

[22]  D. Lilly,et al.  A proposed modification of the Germano subgrid‐scale closure method , 1992 .

[23]  A. Gosman,et al.  Solution of the implicitly discretised reacting flow equations by operator-splitting , 1986 .

[24]  Bert Blocken,et al.  50 years of Computational Wind Engineering: Past, present and future , 2014 .

[25]  E. R. V. Driest.  On Turbulent Flow Near a Wall , 1956 .

[26]  T. G. Thomas,et al.  Mean Flow and Turbulence Statistics Over Groups of Urban-like Cubical Obstacles , 2006 .

[27]  H. Niino,et al.  An Improved Mellor–Yamada Level-3 Model with Condensation Physics: Its Design and Verification , 2004 .

[28]  Manabu Kanda,et al.  Large-Eddy Simulation of Coherent Flow Structures within a Cubical Canopy , 2012, Boundary-Layer Meteorology.

[29]  Michael Schatzmann,et al.  Wind-tunnel and numerical modeling of flow and dispersion about several building shapes , 1999 .

[30]  H. Niino,et al.  Development of an Improved Turbulence Closure Model for the Atmospheric Boundary Layer , 2009 .

[31]  Bje Bert Blocken,et al.  Pedestrian-level wind conditions around buildings: Review of wind-tunnel and CFD techniques and their accuracy for wind comfort assessment , 2016 .

[32]  Yoshihiko Hayashi,et al.  Examining the κ-ϵ model by means of a wind tunnel test and large-eddy simulation of the turbulence structure around a cube , 1990 .

[33]  J. Smagorinsky,et al.  GENERAL CIRCULATION EXPERIMENTS WITH THE PRIMITIVE EQUATIONS , 1963 .

[34]  H. Niino,et al.  An Improved Mellor–Yamada Level-3 Model: Its Numerical Stability and Application to a Regional Prediction of Advection Fog , 2006 .

[35]  M. Raupach,et al.  Conditional statistics of Reynolds stress in rough-wall and smooth-wall turbulent boundary layers , 1981, Journal of Fluid Mechanics.

[36]  Chun-Ho Liu,et al.  Large-Eddy Simulation of Flow and Pollutant Transports in and Above Two-Dimensional Idealized Street Canyons , 2011 .

[37]  Gianluca Iaccarino,et al.  Numerical simulation of scalar dispersion downstream of a square obstacle using gradient-transport type models , 2009 .

[38]  T. Stathopoulos,et al.  Computer simulation of wind environmental conditions around buildings , 1996 .

[39]  Gianluca Iaccarino,et al.  Numerical analysis and modeling of plume meandering in passive scalar dispersion downstream of a wall-mounted cube , 2013 .

[40]  D. Spalding.  A Single Formula for the “Law of the Wall” , 1961 .

[41]  N. Kasagi,et al.  Direct Numerical Simulation of Passive Scalar Field in a Turbulent Channel Flow , 1992 .

[42]  D. Spalding,et al.  A calculation procedure for heat, mass and momentum transfer in three-dimensional parabolic flows , 1972 .

[43]  Gianluca Iaccarino,et al.  A numerical study of scalar dispersion downstream of a wall-mounted cube using direct simulations and algebraic flux models , 2010 .

[44]  Mikio Nakanish,et al.  Improvement Of The Mellor–Yamada Turbulence Closure Model Based On Large-Eddy Simulation Data , 2001 .

[45]  Yoshihide Tominaga,et al.  Cross Comparisons of CFD Results of Wind Environment at Pedestrian Level around a High-rise Building and within a Building Complex , 2004 .

[46]  T. G. Thomas,et al.  Structure of turbulent flow over regular arrays of cubical roughness , 2007, Journal of Fluid Mechanics.

[47]  Wolfgang Rodi,et al.  On the Simulation of Turbulent Flow Past Bluff Bodies , 1993 .

[48]  Yoshihide Tominaga,et al.  Cooperative project for CFD prediction of pedestrian wind environment in the Architectural Institute of Japan , 2007 .

[49]  M. Kanda,et al.  Particle Image Velocimetry Measurements of Turbulent Flow Within Outdoor and Indoor Urban Scale Models and Flushing Motions in Urban Canopy Layers , 2011 .

[50]  A. Martilli,et al.  Comparison Between Large-Eddy Simulation and Reynolds-Averaged Navier–Stokes Computations for the MUST Field Experiment. Part I: Study of the Flow for an Incident Wind Directed Perpendicularly to the Front Array of Containers , 2010 .

[51]  John Kim,et al.  DIRECT NUMERICAL SIMULATION OF TURBULENT CHANNEL FLOWS UP TO RE=590 , 1999 .

[52]  S. Orszag,et al.  Renormalization group analysis of turbulence. I. Basic theory , 1986 .

[53]  W. Rodi.  A new algebraic relation for calculating the Reynolds stresses , 1976 .

[54]  C. Baker.  Wind engineering—Past, present and future , 2007 .

[55]  Bje Bert Blocken,et al.  Quality assessment of Large-Eddy Simulation of wind flow around a high-rise building : validation and solution verification , 2013 .

[56]  Yoshihide Tominaga,et al.  Evaluation of turbulent time scale of linear revised κ-ε models based on LES data , 2006 .

[57]  Bert Blocken,et al.  CFD simulation of near-field pollutant dispersion on a high-resolution grid : a case study by LES and RANS for a building group in downtown Montreal , 2011 .

[58]  Olav R. Hansen,et al.  FLACS CFD air quality model performance evaluation with Kit Fox, MUST, Prairie Grass, and EMU observations , 2004 .

[59]  Akashi Mochida,et al.  Prediction of wind environment and thermal comfort at pedestrian level in urban area , 2006 .

[60]  Yoshihide Tominaga,et al.  CFD Modeling of Pollution Dispersion in Building Array: Evaluation of turbulent scalar flux modeling in RANS model using LES results , 2012 .

[61]  B. Blocken,et al.  CFD simulation of pollutant dispersion around isolated buildings: on the role of convective and turbulent mass fluxes in the prediction accuracy. , 2011, Journal of hazardous materials.

[62]  George C. Efthimiou,et al.  CFD-RANS model validation of turbulent flow in a semi-idealized urban canopy , 2012 .

[63]  Fue-Sang Lien,et al.  A comparison of large Eddy simulations with a standard k–ε Reynolds-averaged Navier–Stokes model for the prediction of a fully developed turbulent flow over a matrix of cubes , 2003 .

[64]  R. Ooka,et al.  A numerical study of air pollutant dispersion with bimolecular chemical reactions in an urban street canyon using large-eddy simulation , 2012 .