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Measurements of Flows Over Isolated Valleys

Abstract

Wind-tunnel measurements of the flow over an isolated valley both normal and at an angle (45°) to a simulated neutrally stable atmospheric boundary layer are presented. Attention is concentrated on the nature of the flow within the valley itself. The work formed part of a wider study that included detailed field measurements around an African desert valley and some limited comparisons with that work are included. A scale of about 1:1000 was used for the laboratory work, in which an appropriate combination of hot wire and particle image velocimetry was employed. For a valley normal to the upwind flow, it is shown that the upstream influence of the valley extends to a distance of at least one half of the axial valley width upstream of the leading edge, whereas differences in mean flow and turbulence could be identified well beyond two valley widths from the downwind edge. Non-normal wind angles lead to significant along-valley flows within the valley and, even at two valley heights above the valley ridge level, there remains a significant spanwise flow component. Downwind turbulence levels are somewhat lower in this case, but are still considerably higher than in the undisturbed boundary layer. At both flow angles, there are significant recirculation regions within the valleys, starting from mean separation just beyond the leading edge, but the strong spanwise flow in the 45° case reduces the axial extent of the separated zone. The flow is shown to be in some ways analogous to flow over an isolated hill. Our results usefully enhance the field data and could be used to improve modelling of saltation processes in the field.

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References

  • P. G. Baines (1995) Topographic effects in Stratified Flow Cambridge University Press U.K. 482

    Google Scholar 

  • R. E. Britter S. A. Hanna (2003) ArticleTitle‘Flow and dispersion in urban areas’ Ann. Rev. Fluid Mech. 35 469–496 Occurrence Handle10.1146/annurev.fluid.35.101101.161147

    Article  Google Scholar 

  • R. E. Britter J. C. R. Hunt K. J. Richards (1981) ArticleTitle‘Air-flow over a two dimensional hill: studies of velocity speed-up, roughness effects and turbulence’ Quart. J. Roy, Meteorol. Soc. 107 91–107 Occurrence Handle10.1256/smsqj.45105

    Article  Google Scholar 

  • J. E. Bullard D. J. Nash (1998) ArticleTitle‘Linear dune pattern variability in the vicinity of dry valleys in the southwest Kalihari’ Geomorphology 11 189–203

    Google Scholar 

  • Busuoli F., Trombetti F., and Tampieri F.: 1993, ‘Data sets for studies of flow and dispersion in complex terrain: II the “RUSVAL” wind tunnel experiment (flow data)’, Tech. Paper 3, FISBAT-TP-93/1, 129 pp.

  • C. Cao P. E. Hancock (2004) ArticleTitle‘Boundary layer development after a region of three-dimensional separation’ Euro. J. Mech. B, Fluids 23 519–533

    Google Scholar 

  • I. P. Castro W. H. Snyder (1982) ArticleTitle‘A wind tunnel study of dispersion from sources downwind of three-dimensional hills’ Atmos.Environ. 16 1869–1887

    Google Scholar 

  • I. P. Castro G. F. S. Wiggs (1994) ArticleTitle‘Pulsed wire anemometry on rough surfaces, with application to desert sand dunes’ J. Wind Eng. & Ind. Aero. 52 53–71

    Google Scholar 

  • I. P. Castro A. Haque (1986) ArticleTitle‘The structure of a turbulent shear layer bounding a separation region’ J. Fluid Mech. 179 439–468

    Google Scholar 

  • I. P. Castro E. Epik (1996) ArticleTitle‘Development of boundary layers after regions of separation’ J. Fluid Mech. 374 91–116

    Google Scholar 

  • J. J. Finnigan M. R. Raupach E. F. Bradley G. K. Aldis (1990) ArticleTitle‘A wind tunnel study of turbulent flow over a two-dimensional ridge’ Boundary-layer Meteorol. 50 277–317 Occurrence Handle10.1007/BF00120527

    Article  Google Scholar 

  • B. G. Garvey (2003) ‘Wind flow over dryland valleys and implications for aeolian sediment transport’ University of Sheffield U.K.

    Google Scholar 

  • Garvey, B., Wiggs, G. F. S., Castro, I. P. and Bullard, J. E.: 2002, ‘Wind tunnel investigations of flow dynamics within and around a valley’, Proc. of 5th U.K. Conf. On Wind Engineering. U.K. Wind Engineering Society, pp. 61–64.

  • A. L. M. Grant (1992) ArticleTitle‘The structure of turbulence in the near-neutral atmospheric boundary layer’ J. Atmos. Sci. 49 226–239

    Google Scholar 

  • J. C. R. Hunt S. Leibovich K. J. Richards (1988) ArticleTitle‘Turbulent shear flow over low hills’ Quart. J. Roy. Meteorol. Soc. 114 1435–1470

    Google Scholar 

  • H. P. A. H. Irwin (1981) ArticleTitle‘The design of spires for wind stimulation’ J. Wind Eng. Ind. Aero. 7 361–366

    Google Scholar 

  • P. S. Jackson (1977) ArticleTitle‘Aspects of surface wind behaviour’ Wind Engineering 1 1–14

    Google Scholar 

  • P. S. Jackson J. C. R. Hunt (1975) ArticleTitle‘Turbulent flow over a low hill’ Quart. J. Roy. Meteorol. Soc. 101 929–955 Occurrence Handle10.1256/smsqj.43014

    Article  Google Scholar 

  • J. C. Kaimal J. J. Finnigan (1994) Atmospheric Boundary Layer Flows: Their Structure and Measurement Oxford University Press New York 289

    Google Scholar 

  • Khurshudyan, L. H., Snyder, W. H., Nekrasov, R. E., Lawson, R. E., Thompson, R. S. and Schiermeier, F. A.: 1990, ‘Flow and dispersion of pollutants within two dimensional valleys: summary report on joint Soviet-American study’, Tech. Rpt. EPA-600/3-90-025, Res. Tri. Pk., NC.

  • F. Kimura P. Manins (1988) ArticleTitle‘Blocking in periodic valleys’ Bound. Layer Meteorol. 44 137–169 Occurrence Handle10.1007/BF00117296

    Article  Google Scholar 

  • N. Lancaster (1988) ArticleTitle‘Development of linear dunes in the southwest Kalihari, southern Africa’ H. Arid Environ. 14 233–244

    Google Scholar 

  • P. Louka S. E. Belcher R. G. Harrison (2000) ArticleTitle‘Coupling between air flow in streets and the well-developed boundary layer aloft’ Atmos. Environ. 34 2613–2621 Occurrence Handle10.1016/S1352-2310(99)00477-X

    Article  Google Scholar 

  • S. R. McLean J. M. Nelson R. L. Shreve (1996) Flow sediment interactions in separating flow over bed-forms P. J. Ashworth (Eds) ‘Coherent flow structures in open channels’ Wiley Publishers Chichester 203–226

    Google Scholar 

  • P. N. Shankar M. D. Deshpande (2000) ArticleTitle‘Fluid mechanics in the driven cavity’ Ann. Rev. Fluid Mech. 32 93–136 Occurrence Handle10.1146/annurev.fluid.32.1.93

    Article  Google Scholar 

  • P. Sierputowski J. Ostrowski A. Cenedesa (1995) ArticleTitle‘Experimental study of wind flow over the model of a valley’ J. Wind Eng. Ind. Aero. 57 127–136

    Google Scholar 

  • W. H. Snyder L. H. Khurshudyan R. E. Nekrasov R. E. Lawson R. S. Thompson (1991) ArticleTitle‘Flow and dispersion of pollutants within two-dimensional valleys’ Atmos. Environ. A25 1347–1375

    Google Scholar 

  • Tsaor, H., Rasmussen, K. R., Sorenson, M. and Willetts, B. B.: 1985, ‘Laboratory study of flow over dunes’, In Proc., of Int. Workshop on Physics of Blown Sand, Memoirs 8, Dept. of Theoretical Statistics, Aarhus University.

  • R. O. Weber P. Kaufmann (1998) ArticleTitle‘Relationship of synoptic winds and complex terrain flows during the MISTRAL field experiment’ J. Appl. Meteorol. 37 1486–1496 Occurrence Handle10.1175/1520-0450(1998)037<1486:ROSWAC>2.0.CO;2

    Article  Google Scholar 

  • G. F. S. Wiggs J. E. Bullard B. G. Garvey I. P. Castro (2002) ArticleTitle‘Interactions between airflow and valley topography with implications for aeolian sediment transport’ Physical Geography 21 366–380

    Google Scholar 

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Correspondence to Ian P. Castro.

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Garvey, B., Castro, I.P., Wiggs, G. et al. Measurements of Flows Over Isolated Valleys. Boundary-Layer Meteorol 117, 417–446 (2005). https://doi.org/10.1007/s10546-005-2079-6

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  • DOI: https://doi.org/10.1007/s10546-005-2079-6

Keywords

  • Isolated valleys
  • Boundary layer
  • Wind-tunnel