Oblique, stratified winds about a shelter fence. Part II: Comparison of measurements with numerical models

Abstract To evaluate Reynolds-averaged Navier–Stokes (RANS) models of disturbed micrometeorological winds, steady-state computations using a second-order closure are compared with observations (see Part I) in which the surface layer wind was disturbed by a long, thin porous fence (height h = 1.25 m; thickness dx ≈ 1 mm). Starting with the case of neutral stratification and normal incidence, it is shown that low-resolution RANS simulations (streamwise grid interval Δx/h = 1) produce reasonably good transects of mean wind speed, though with an ambiguity (or nonuniqueness) of at least 10%–15% of the amplitude of the relative wind curve, mainly arising from sensitivity to the choice of the solution mesh. For nearly perpendicular flows, the measured influence of stratification (stable or unstable) is to diminish the amplitude of the relative wind curve (i.e., windbreak is less effective), an effect that is replicated very well by the simulations. Obliquity of the incident wind, like stratification, also correl...

[1]  Frank Thiele,et al.  Comparison of LES and RANS in bluff-body flows , 2001 .

[2]  P. Durbin.  A Reynolds stress model for near-wall turbulence , 1993, Journal of Fluid Mechanics.

[3]  On shelter efficiency of shelterbelts in oblique wind , 1996 .

[4]  E. F. Bradley,et al.  THE TURBULENT KINETIC ENERGY BUDGET BEHIND A POROUS BARRIER: AN ANALYSIS IN STREAMLINE CO-ORDINATES , 1983 .

[5]  Thomas K. Flesch,et al.  Wind Measurements in a Square Plot Enclosed by a Shelter Fence , 2003 .

[6]  J. C. Kaimal,et al.  Atmospheric boundary layer flows , 1994 .

[7]  W. S. Lewellen,et al.  Prediction of the Monin-Obukhov Similarity Functions from an Invariant Model of Turbulence , 1973 .

[8]  J. Palma,et al.  Simulation of the Askervein Flow. Part 1: Reynolds Averaged Navier–Stokes Equations (k∈ Turbulence Model) , 2003 .

[9]  E. Takle,et al.  A numerical simulation of boundary-layer flows near shelterbelts , 1995 .

[10]  M. Carbonaro,et al.  von Karman Institute for Fluid Dynamics , 2004 .

[11]  T. Prenosil.  Prediction of the Monin-Obukhov similarity functions from a second-order-closure model , 1979 .

[12]  Klaus Bremhorst,et al.  Large-eddy simulation of heat transfer downstream of a backward-facing step , 2004 .

[13]  D. C. Stevenson,et al.  Wind protection by model fences in a simulated atmospheric boundary layer , 1977 .

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

[15]  N. Wilson,et al.  A Higher Order Closure Model for Canopy Flow , 1977 .

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

[17]  John D. Wilson,et al.  Numerical studies of flow through a windbreak , 1985 .

[18]  E. M. Laws,et al.  Flow Through Screens , 1978 .

[19]  Wolfgang Kollmann,et al.  Prediction Methods for Turbulent Flows , 1980 .

[20]  M. Raupach,et al.  Averaging procedures for flow within vegetation canopies , 1982 .

[21]  E. F. Bradley,et al.  Development of velocity and shear stress distribution in the wake of a porous shelter fence , 1983 .

[22]  John D. Wilson.  Oblique, Stratified Winds about a Shelter Fence. Part I: Measurements , 2004 .

[23]  George L. Mellor,et al.  Analytic Prediction of the Properties of Stratified Planetary Surface Layers , 1973 .

[24]  H. L. Dryden,et al.  THE EFFECT OF WIRE GAUZE ON SMALL DISTURBANCES IN A UNIFORM STREAM , 1949 .

[25]  Eugene S. Takle,et al.  Boundary-layer flow and turbulence near porous obstacles , 1995 .

[26]  John D. Wilson,et al.  Comments on ’a Numerical Simulation of Boundary-Layer Flows Near Shelterbelts‘ by H. Wang and E. Takle , 1997 .

[27]  T. Flesch,et al.  Micro-meteorological methods for estimating surface exchange with a disturbed windflow , 2001 .

[28]  Fue-Sang Lien,et al.  Numerical modelling of the turbulent flow developing within and over a 3-d building array, part ii: a mathematical foundation for a distributed drag force approach , 2005 .

[29]  E. F. Bradley,et al.  DEVELOPMENT OF VELOCITY AND SHEAR STRESS DISTRIBUTIONS IN THE WAKE OF A POROUS SHELTER FENCE , 1984 .

[30]  P. Durbin.  Near-wall turbulence closure modeling without “damping functions” , 1991, Theoretical and Computational Fluid Dynamics.

[31]  S. Green.  Modelling Turbulent Air Flow in a Stand of Widely-Spaced Trees , 1992 .

[32]  J. Finnigan,et al.  Turbulent Transport in Flexible Plant Canopies , 1985 .

[33]  Eugene Yee,et al.  Calculation of winds disturbed by an array of fences , 2003 .

[34]  John L. Lumley,et al.  Computational Modeling of Turbulent Transport , 1975 .

[35]  J. Wyngaard,et al.  Local advection of momentum, heat, and moisture in micrometeorology , 1974 .

[36]  A. D. Gosman,et al.  Developments in CFD for industrial and environmental applications in wind engineering , 1999 .

[37]  John D. Wilson,et al.  On the choice of a windbreak porosity profile , 1987 .

[38]  K. Mcnaughton.  Micrometeorology of shelter belts and forest edges , 1989 .

[39]  G.P.A. Bot,et al.  Wind-induced airflow through permeable materials, Part I: the motion equation , 2001 .

[40]  Margitta Nord,et al.  Shelter effects of vegetation belts — Results of field measurements , 1991 .

[41]  N. Bink.  The structure of the atmospheric surface layer subject to local advection , 1996 .

[42]  E. F. Bradley,et al.  An alternative analysis of flux-gradient relationships at the 1976 ITCE , 1982 .

[43]  Remi Manceau,et al.  A new form of the elliptic relaxation equation to account for wall effects in RANS modeling , 2000 .

[44]  John D. Wilson,et al.  A second-order closure model for flow through vegetation , 1988 .

[45]  Brian Launder,et al.  Second-moment closure: present… and future? , 1989 .