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Air flow and turbulence over complex terrain: a colloquium and a computational workshop

Published online by Cambridge University Press:  26 April 2006

J. C. R. Hunt ,
F. Tampieri ,
W. S. Weng  and
D. J. Carruthers
J. C. R. Hunt
Affiliation:
Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Silver Street, Cambridge CB3 9EW, UK
F. Tampieri
Affiliation:
Institute FISBAT - CNR, Bologna, Italy
W. S. Weng
Affiliation:
Cambridge Environmental Research Consultants Ltd, 3D King's Parade, Cambridge CB2 1SJ, UK
European Research Community On Flow Turbulence And Combustion.
D. J. Carruthers
Affiliation:
Cambridge Environmental Research Consultants Ltd, 3D King's Parade, Cambridge CB2 1SJ, UK
European Research Community On Flow Turbulence And Combustion.
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Abstract

The third Euromech Colloquium on this topic was held at FISBAT in Bologna in August 1990, in succession to those in 1979 at Munich (No. 113) and 1983 at Delphi (No. 173). About 30 participants came from 10 countries. At the Colloquium it became clear that there have been some significant developments since 1983 in theoretical analysis, computational modelling and field experiments, with new kinds of measurement. As well as papers on improvements in the quantification and understanding of the main, well-known features of these flows, there were also papers on phenomena that had not previously been studied; for example new computations of flows over undulating surfaces driven by buoyancy forces, caused by heating the surface, showed that secondary flows are produced with vorticity parallel to the undulations, while wind tunnel experiments on flows perpendicular to the crests showed secondary flow with vorticity perpendicular to the crests, and with a scale consistent with Craik's (1982) theory which predicted these novel kinds of Langmuir cells. The magnitude of the net drag force on undulating surfaces in neutrally stratified turbulent flows now appears to be moderately well established by different methods, including computations, laboratory experiments, and theoretical analyses. These have clarified the relative magnitudes of a number of contributing mechanisms. The role of Coriolis accelerations (f) in atmospheric flow over simple terrain features (lengthscale L, height H) on the mesoscale (order 30 km upwards) is now better understood. For stratified air flow impinging onto hills rising from a flat plain the Rossby radius (lR = HN/f) is the relevant lengthscale (where N is the buoyancy frequency), but in neutral or convective conditions, such as those which occur when southerly winds are channelled down the Rhine valley, the turning of the wind on a scale of the terrain less than the Rossby radius can also be significantly influenced by Coriolis accelerations.

The recent field measurements by Doppler-sodar (which are installed in several French power stations) produce useful data for comparing with computational models; they also emphasize the need to solve the theoretical question of how best to combine model calculations and measurements within the flow field that exceed the number required to specify the flow in the model. Models of the mean flow and the turbulence have improved to the extent that they can be used in other scientific and practical problems, such as being incorporated into models of dispersion of pollutants, or in models of microphysics and chemical processes in polluted clouds over hills.

Following the Colloquium an ERCOFTACt Workshop was held in which the computer codes of such models were presented and compared in detail. It was decided that i t is necessary to have a systematic intercomparison of such codes, and also detailed comparisons with the extensive sets of data now available from recent field and laboratory experiments.

The wide range of scales that occur in these complex atmospheric flows (10−2 m to 105 m) all have to be considered and calculated in detail, because simple assumptions about the flow (such as that the mean velocity has a logarithmic profile up to a significant height above the surface) are erroneous. Computational models were described that range in complexity from those based on analytical solutions (at low computational cost) to those based on solving discretized equations with large variations in grid sizes to accommodate the range of scales. Novel interactive software was used that enables graphs from different models to be requested and then rapidly displayed simultaneously on a screen for comparisons to be made. This software opens out significant new possibilities for scientific meetings and workshops involving computational fluid dynamics.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 227 , June 1991 , pp. 667 - 688
Copyright
© 1991 Cambridge University Press

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References

Alessio, S., Briatore, L. & Longhetto, A. 1983 Laboratory simulation of rotating atmospheric boundary layer flows over obstacles. Nuovo Cimento 6, 401–428.Google Scholar
Anfossi, D., Ferrero, E., Brusasca, G., Tinarelli, M., Glostra, U., Tampieri, F. & Trombetti, F. A random walk model suitable for dealing with isolated source dispersion in flows over hills.
Anthes, R. A., Kuo, Y., Hsie, E., Low-Nam, S. & Bettge, T. W. 1989 Evaluation of skill and uncertainty in regional numerical models. Q. J. R. Met. Soc. 115, 763–806.Google Scholar
Baas, A. F. De, Dop, H. van & Nieuwstadt, F. T. M. 1986 An application of the Langevin equation for inhomogeneous conditions to dispersion in a convective boundary layer. Q. J. R. Met. Soc. 112, 165–180.Google Scholar
Belcher, S. E. 1991 Turbulent boundary layer flow over undulating surfaces. Ph.D. dissertation, University of Cambridge.
Beljaars, A. C. M., Walmsley, J. L. & Taylor, P. A. 1987 A mixed spectral finite-difference model for neutrally stratified boundary-layer flow over roughness changes and topography. Boundary-Layer Met. 38, 273–303.Google Scholar
Beniston, M., Walf, J. R., Beniston-Rebetez, M., Koelsch, H. J., Rairoux, P. & Woeste, L. 1990 Use of LIDAR measurements and numerical models in air pollution research. J. Geophys. Res. 95D, 9879–9894.Google Scholar
Blumen, W. 1984 An observational study of instability and turbulence in night time drainage winds. Boundary-Layer Met. 28, 245–259.Google Scholar
Blumen, W. 1990 (Ed.) Atmospheric Processes over Complex Terrain. Am. Met. Soc. Meteorological monographs, vol. 23, no. 45. Lancaster.
Britter, R. E., Hunt, J. C. R. & Richards, K. J. 1981 Air flow over a two-dimensional hill: studies of velocity speed-up, roughness effects and turbulence. Q. J. R. Met. Soc. 107, 31–110.Google Scholar
Buizza, R., Morselli, M. G. & Brusasca, G., Package ICARO ENEL Italy.
Carruthers, D. J. & Choularton, T. W. 1984 Acid deposition in rain over hills. Atmos. Environ. 18, 1901–1908.Google Scholar
Carruthers, D. J. & Choularton, T. W. 1986 The microstructure of hill cap clouds. Q. J. R. Met. Soc. 112, 113–129.Google Scholar
Carruthers, D. J. & Hunt, J. C. R. 1990 Fluid mechanics of airflow over hills: turbulence, fluxes, and winds in the boundary layer. In Atmospheric Processes over Complex Terrain (ed. W. Blumen) Am. Met. Soc., Meteorological Monographs vol. 23, no. 45, pp. 83–107 Lancaster.
Chauve, M. P. & Schiestel, R. 1985 Influence of wall undulations on the structure of turbulent pipe flow, an experimental and numerical study. J. Fluid Mech. 160, 67–85.Google Scholar
Chollet, J. P. & Lesieur, M. 1981 Parameterization of small scales of three-dimensional isotropic turbulence utilizing spectral closures. J. Atmos. Sci. 38, 2747–2757.Google Scholar
Craik, A. D. D. 1982 Wave-induced longitudinal-vortex instability in shear flows. J. Fluid Mech. 125, 35–72.Google Scholar
Dalu, G. A., Baldi, M., Guerrini, A. & Pielke, R. A. Impact of terrain thermal inhomogeneities on mesoscale atmospheric flow with zero synoptic wind.
Drazin, P. G. 1961 On the steady flow of a fluid of variable density past an obstacle. Tellus 13, 239–251.Google Scholar
Egan, B. A. 1984 Transport and diffusion in complex terrain. Boundary-Layer Met. 30, 3–28.Google Scholar
Fiedler, F. 1987 Atmospheric transport of air pollutants in the middlescale wet hilly terrain: a review of the TULLA experiment. In Regional and Long Range Transport of Air Pollution (ed. F. Sandroni). Elsevier.
Finnigan, J. J. 1988 Airflow over complex terrain. In Flow and Transport in the Natural Environment: Advances and Applications (ed. W. K. Steffen & O. T. Benmead), pp. 183–229. Springer.
Fitzjarrald, D. R. 1984 Katabatic wind in opposing flow. J. Atmos. Sci. 41, 1143–1158.Google Scholar
Gerz, T., Schumann, U. & Elghobashi, S. E. 1989 Direct numerical simulation of stratified homogeneous turbulent shear flows. J. Fluid Mech. 200, 563–594.Google Scholar
Hunt, J. C. R. 1973 A theory of turbulent flow round two-dimensional bluff bodies. J. Fluid Mech. 61, 625–706.Google Scholar
Hunt, J. C. R. 1985 Turbulent diffusion from sources in complex flows. Ann. Rev. Fluid Mech. 17, 447–485.Google Scholar
Hunt, J. C. R., Lalas, D. P. & Asimakopoulos, D. N. 1984 Air flow and dispersion in rough terrain: a report on Euromech 173. J. Fluid Mech. 142, 201–216.Google Scholar
Hunt, J. C. R., Leibovich, S. & Richards, K. J. 1988a Turbulent shear flows over low hills. Q. J. R. Met. Soc. 114, 1435–1470.Google Scholar
Hunt, J. C. R., Moin, P., Lee, M., Moser, R. D., Spalart, P., Mansour, N. N., Kaimal, J. C. & Gaynor, E. 1989 Cross correlation and length scales in turbulent flows near surfaces. In Advances in Turbulence 2 (ed. H. H. Fernholz & H. E. Fiedler), pp. 128–134. Springer.
Hunt, J. C. R., Newley, T. M. J. & Weng, W. S. 1990 Analysis and computation of turbulent boundary layers with varying pressure gradients. In Proc. IMA Conf. on Computational Method in Aeronautic Fluid Dynamics (ed. P. Stow), pp. 59–92. Clarendon.
Hunt, J. C. R., Richards, K. J. & Brighton, P. W. M. 1988b Stratified shear flow over low hills. Q. J. R. Met. Soc. 114, 819–886.Google Scholar
Jackson, P. S. & Hunt, J. C. R. 1975 Turbulent wind flow over a low hill. Q. J. R. Met. Soc. 101, 929–955.Google Scholar
Jacobs, S. T. 1987 An asymptotic theory for the turbulent flow over a progressive wave. J. Fluid Mech. 174, 69–80.Google Scholar
Jeffreys, H. 1925 On the formation of water waves by wind.. Proc. R. Soc. Lond. A 107, 189–206.Google Scholar
Jensen, N. O. & Peterson, E. W. 1978 On the escarpment wind profile. Q. J. R. Met. Soc. 104, 719–728.Google Scholar
Kaimal, J. C., Eversole, R. A., Lenschow, D. H., Stankov, B. B., Kahn, P. H. & Businger, J. A. 1982 Spectral characteristics of convective boundary layer over uneven terrain. Q. J. R. Met. Soc. 39, 1098–1114.Google Scholar
Khurshudyan, L. H., Snyder, W. H. & Nekrasov, I. V. 1981 Flow and dispersion of pollutants over two-dimensional hills. EPA-600/4-81-067 (available from ESRL, U.S. EPA, Research Triangle Park, NC 27711).Google Scholar
Kiya, M., Ohyama, M. & Hunt, J. C. R. 1986 Vortex pairs and rings interacting with shear layer vortices. J. Fluid Mech. 175, 1–15.Google Scholar
Klemp, J. B. & Lilly, D. K. 1975 The dynamics of wave-induced downslope winds. J. Atmos. Sci. 32, 320–339.Google Scholar
Kraichnan, R. H. 1966 Isotropic turbulence and inertial-range structure. Phys. Fluids 9, 1728–1752.Google Scholar
Krettenauer, K. & Schumann, U. 1989 Direct numerical simulation of thermal convection over a wavy surface. Met. Atmos. Phys. 41, 165–179.Google Scholar
Kuo, Y.-H., Skumarich, P. L., Haagenson, P. L. & Chong, J. S. 1985 Accuracy of air parcel trajectories as revealed by the observing system simulation experiments. Mon. Weath. Rev. 113, 1852–1867.Google Scholar
Launder, B. E., Reece, G. T. & Rodi, W. 1975 The development of a Reynolds stress turbulent closure. J. Fluid Mech. 68, 537–566.Google Scholar
Lavery, T. F., Strimaitis, D. G., Venkatram, A., Greene, B. R., Dicristofaro, D. C. & Egan, A. 1983 EPA Complex Terrain Model development: third milestone report. EPA-600/3-83-101 (available from NTIS, US Dept. of Commerce, Springfield, VA, 22181).
Lesieur, M. & Rogallo, R. 1989 Large-eddy simulation of passive-scalar diffusion in isotropic turbulence.. Phys Fluids A 1, 718–722.Google Scholar
Lewellen, W. S., Sykes, R. I. & Oliver, D. 1982 The evolution of MATHEW/ADPIC as a real time dispersion model. Aeronautical Res. Assoc. of Princeton Inc., Rep. 422 for Div. Health, Safety and Waste Management, Office of Nuclear Regulatory Res., US Nuclear Regulatory Commission.
Lopes, A. G. & Viegas, D. X. 1990 Wind tunnel simulation of the influence of the wind characteristics on the propagation of forest fires in canyon shaped hills In Proc. Intl. Conf. on Forest Fire Research, pp. B10-1-B10-11. Coimbra, Portugal.
Louis, J. R. 1979 The parametrization of the planetary boundary layer. ECMWF Lecture Note no. 9 (available from ECMWF, Reading, Berks, UK).Google Scholar
Mcnider, R. T. & Pielke, R. A. 1981 Diurnal boundary layer development over sloping terrain. J. Atmos. Sci. 38, 2198–2212.Google Scholar
Maryon, R. H., Whitlock, J. B. G. & Jenkins, G. J. 1984 An analysis of short-range dispersion experiments on the windward slope of an isolated hill. Atmos. Environ. 20, 2157–2174.Google Scholar
Mason, P. J. & Derbyshire, S. H. 1990 Large eddy simulation of the stably-stratified atmospheric boundary layer. Boundary-Layer Met. 53, 117–162.Google Scholar
Mason, P. J. & King, J. C. 1985 Measurements and predictions of flow and turbulence over an isolated hill of moderate slope. Q. J. R. Met. Soc. 111, 617–640.Google Scholar
Mason, P. J. & Sykes, R. I. 1979 On the net forces produced by surface-mounted obstacles. Q. J. R. Met. Soc. 105, 829–840.Google Scholar
Merkine, L. O. 1975 Steady finite-amplitude homoclinic flow over long topography in a rotating, stratified atmosphere. J. Atmos. Sci. 32, 1881–1893.Google Scholar
Mickle, R. E., Cook, N. J., Hoff, A. M., Jensen, N. D., Salmon, J. R., Taylor, P. A., Tetzloff, G. & Tennisen, H. W. 1988 The Askervein hill project: vertical profiles of wind and turbulence. Boundary-Layer Met., 43, 143–169.Google Scholar
Neish, A. & Smith, F. T. 1991 On turbulent separation in the flow past bluff bodies. J. Fluid Mech. (submitted).Google Scholar
Newley, T. M. J. 1986 Turbulent air flow over hills. Ph.D. thesis, University of Cambridge.
Newley, T. M. J., Pearson, H. J. & Hunt, J. C. R. 1991 Stably stratified rotating flow through a group of obstacles. Geophys. Astrophys. Fluid Dyn. (to appear).Google Scholar
Oke, T. R. 1978 Boundary Layer Climates. John Wiley & Sons.
Peltier, W. R. & Clark, T. L. 1983 Nonlinear mountain waves in two and three spatial dimensions. Q. J. R. Met. Soc. 109, 527–548.Google Scholar
Perry, S. G. & Finkelstein, P. L. 1990 The US Environmental Protection Agency's model for complex terrain applicants. Proc. 10th Intl Conf. of Clean Air Sec. of Australia & New Zealand.
Pielke, R. A. 1984 Mesoscale Meteorological Modelling. Academic.
Schmidt, H. & Schumann, U. 1989 Coherent structure of the convective boundary layer derived from large-eddy simulations. J. Fluid Mech. 200, 511–562.Google Scholar
Schumann, U. 1990 Large-eddy simulation of the up-slope boundary layer. Q. J. R. Met. Soc. 116, 637–670.Google Scholar
Schumann, U. & Schmidt, H. 1989 Heat transfer by thermals in the convective boundary layer. In Advances in Turbulence 2 (ed. H.-H. Fernholz & H. E. Fiedler), pp. 210–215. Springer.
Scorer, R. S. 1955 Theory of airflow over mountains. Part III. Separation of flows from the surface. Q. J. R. Met. Soc. 81, 360–380.Google Scholar
Sherman, C. 1978 A mass consistent model for wind fields over complex terrain. J. Appl. Met. 17, 312–319.Google Scholar
Smagorinsky, J. 1963 General circulation experiments with the primitive equation, I. The basic experiment. Mon. Weath. Rev. 91, 99–164.Google Scholar
Smith, R. B. 1980 Linear theory of stratified hydrostatic flow past an isolated mountain. Tellus 32, 358–364.Google Scholar
Smolarkiewicz, P. K. & Rotunno, R. 1990 Low Froude number flow past 3-D obstacles. Part II. Upwind flow reversal zone. J. Atmos. Sci. 47, 1498–1511.Google Scholar
Snyder, W. H., Thompson, R. S., Eskridge, R. E., Lawson, R. E., Castro, I. P., Lee, J. T., Hunt, J. C. R. & Ogawa, Y. 1985 The structure of strongly stratified flow over hills: dividing-streamline concept. J. Fluid Mech. 152, 249–288.Google Scholar
Stern, M. E. 1975 Minimal properties of planetary eddies. J. Mar. Res. 33, 239–267.Google Scholar
Sykes, R. J. 1980 An asymptotic theory of incompressible turbulent boundary layer flow over a small hump. J. Fluid Mech. 107, 607–670.Google Scholar
Tampieri, F. 1987 Separation features of boundary layer flow over valleys. Boundary-Layer Met. 40, 295–307.Google Scholar
Tampieri, F. & Hunt, J. C. R. 1986 Stratified flow and wave motion near mountain tops. Proc. Conf. on the Scientific Results of the Alpine Experiment (ALPEX),July 1985. GARP Publication Series No. 27, pp. 359–369. Geneva, WMO.
Taylor, P. A. 1977 Some numerical studies of surface boundary layer flow above gentle topography. Boundary-Layer Met. 11, 439–465.Google Scholar
Taylor, P. A. & Gong, W. 2-D finite difference modelling of turbulent boundary layer flow over topography.
Taylor, P. A., Mason, P. J. & Bradley, E. F. 1987 Boundary layer flow over low hills. Boundary-Layer Met. 39, 107–132.Google Scholar
Taylor, P. A., Sykes, R. I. & Mason, P. J. 1989 On the parameterization of drag over small scale topography in neutrally-stratified boundary-layer flow. Boundary-Layer Met. 48, 409–422.Google Scholar
Thomson, D. J. 1986 A random walk model of dispersion in turbulent flows and its application to dispersion in a valley. Q. J. R. met Soc. 112, 511–530.Google Scholar
Thukier-Nielson, T., Mikkelsen, S. E., Lensen, S. E., Troen, I., Baas, A. F. de, Kamada, R., Shupniewig, C. & Schachen, L. 1989 A model for accidental releases in complex terrain. In Air Pollution Modeling and its Application VII (ed. H. van Dop), pp. 65–87. Plenum.
Townsend, A. A. 1972 Flow in a deep turbulent layer over a surface distorted by water waves. J. Fluid Mech. 55, 715–735.Google Scholar
Traci, R. M., Phillips, G. T., Patnaik, P. C. & Freeman, B. E. 1977 Development of a wind energy methodology. US Dept. Energy, Rep. RLO/2440-11, 205pp.Google Scholar
Walmsley, J. L., Salmon, J. R. & Taylor, P. A. 1982 On the application of a model of boundary layer flow over low hills to real terrain. Boundary-Layer Met. 23, 17–46.Google Scholar
Walmsley, J. L., Taylor, P. A. & Keith, T. 1986 A simple model of neutrally stratified boundary layer flow over complex terrain with surface roughness modulations (MS3DJH/3R). Boundary-Layer Met. 36, 157–186.Google Scholar
Weng, W. S. & Carruthers, D. J. A shear-blocking mixing length model for turbulent boundary layer flow.
Weng, W. S., Hunt, J. C. R., Carruthers, D. J., Warren, A., Wiggs, G. F. S., Livingstone, I. & Castro, I. 1990 Airflow and sand transport over sand dunes. In Proc. Conf. on Sand, Dust and Soil and their Relation to Aeolian and Littoral Processes (ed. O. E. Barndoff-Nielsen & B. B. Willets (to appear in Acta Mechanica).
Wippermann, F. 1983 Air flow over and in broad valleys: channeling and counter-current. Beilr. Z. Phys. Atmos. 57, 92–105.Google Scholar
Wong, H. Y. W. 1985 Shear-free turbulence and secondary flow near angled and curved surface. Ph.D. thesis, University of Cambridge.
Zeman, O. & Jensen, N. O. 1987 Modification of turbulence characteristics in flow over hills. Q. J. R. Met. Soc. 113, 55–80.Google Scholar
Zilker, D. P., Cook, G. W. & Hanratty, T. S. 1977 Influence of the amplitude of a solid wave wall on a turbulent flow. Part 1. Non-separated flows. J. Fluid Mech. 82, 29–51.Google Scholar
Zilker, D. P. & Hanratty, D. S. 1979 Influence of the amplitude of a solid wavy wall on a turbulent flow. Part 2. Separated flows. J. Fluid Mech. 90, 257–271.Google Scholar