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Comparison of Speed-Up Over Hills Derived from Wind-Tunnel Experiments, Wind-Loading Standards, and Numerical Modelling

Boundary-Layer Meteorology volume 168, pages 213–246 (2018)Cite this article

Abstract

We evaluate the accuracy of the speed-up provided in several wind-loading standards by comparison with wind-tunnel measurements and numerical predictions, which are carried out at a nominal scale of 1:500 and full-scale, respectively. Airflow over two- and three-dimensional bell-shaped hills is numerically modelled using the Reynolds-averaged Navier–Stokes method with a pressure-driven atmospheric boundary layer and three different turbulence models. Investigated in detail are the effects of grid size on the speed-up and flow separation, as well as the resulting uncertainties in the numerical simulations. Good agreement is obtained between the numerical prediction of speed-up, as well as the wake region size and location, with that according to large-eddy simulations and the wind-tunnel results. The numerical results demonstrate the ability to predict the airflow over a hill with good accuracy with considerably less computational time than for large-eddy simulation. Numerical simulations for a three-dimensional hill show that the speed-up and the wake region decrease significantly when compared with the flow over two-dimensional hills due to the secondary flow around three-dimensional hills. Different hill slopes and shapes are simulated numerically to investigate the effect of hill profile on the speed-up. In comparison with more peaked hill crests, flat-topped hills have a lower speed-up at the crest up to heights of about half the hill height, for which none of the standards gives entirely satisfactory values of speed-up. Overall, the latest versions of the National Building Code of Canada and the Australian and New Zealand Standard give the best predictions of wind speed over isolated hills.

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Notes

  1. Therefore, for future work, before applying the proposed profiles in Fluent, it is essential to understand the differences in wall treatment between the Fluent and CFX packages, and to modify the profiles in such a way that they produce a homogeneous ABL in the Fluent software.

References

  • ANSYS Inc. (2011) ANSYS CFX-pre user’s guide. ANSYS Inc., Southpointe, Canonsburg

  • AS/NZS1170.2 (2011) Australia/New Zealand Standard, Structural design actions, Part 2: wind actions. Jointly published by Standards Australia Limited/Standards New Zealand, Sydney, NWS and Wellington

  • ASCE-7 (2016) Minimum design loads and associated criteria for buildings and other structures. American Society of Civil Engineers, Reston

    Google Scholar 

  • Australian Standard (1989) Australian Standard, SAA Loading code, part 2: wind loads. Standards Australia, North Sydney

  • Balogh M, Parente A, Benocci C (2012) RANS simulation of ABL flow over complex terrains applying an Enhanced k–ε model and wall function formulation: implementation and comparison for fluent and OpenFOAM. J Wind Eng Ind Aerodyn 104–106:360–368

    Article  Google Scholar 

  • Bilal M, Sridhar N, Araya G, Parameswaran S, Brikelund Y (2015) Wind flow over a complex terrain in Nygardsfjell, Norway. In: ASME 9th international conference on energy sustainability, June 28–July 2 2015, San Diego, CA, pp 1–9

  • Bitsuamlak G, Stathopoulos T, Bedard C (2004) Numerical modelling of wind flow over different types of topography. Structures Congress: building on the past, securing the future, 22–26 May, 2004, Nashville, Tennessee, USA, pp 1–11

  • Blocken B, Carmeliet J (2004) Modelling atmospheric boundary-layer flow with Fluent: curing the wall-function roughness incompatibility. The Fluent Benelux User Group Meeting, 5–6 October, 2004, Leuven, Belgium

  • Blocken B, Carmeliet J (2006) The influence of the wind-blocking effect by a building on its wind-driven rain exposure. J Wind Eng Ind Aerodyn 94(2):101–127

    Article  Google Scholar 

  • Blocken B, Stathopoulos T, Carmeliet J (2007) CFD simulation of the atmospheric boundary layer: wall function problems. Atmos Environ 41:238–252

    Article  Google Scholar 

  • Blocken B, Hout AVD, Dekker J, Weiler O (2015) CFD simulation of wind flow over natural complex terrain: case study with validation by field measurements for Ria de Ferrol, Galicia, Spain. J Wind Eng Ind Aerodyn 147:43–57

    Article  Google Scholar 

  • Bowen AJ (1983) The prediction of mean wind speeds above simple 2D hill shape. J Wind Eng Ind Aerodyn 15:259–270

    Article  Google Scholar 

  • Breuer M, Peller N, Rapp C, Manhart M (2009) Flow over periodic hills—numerical and experimental study in a wide range of Reynolds numbers. Comput Fluids 38:433–457

    Article  Google Scholar 

  • BS NA EN 1991-1-4 (2010) (English): UK National Annex to Eurocode 1. Actions on structures. General actions. Wind actions

  • BS6399-2 (1997) Loading for buildings—part 2: code of practice for wind loads. Published under the authority of the Standards Board, BSI 10-1998

  • Cao S, Wang T, Ge Y, Tamura Y (2012) Numerical study on turbulent boundary layers over two-dimensional hills—effects of surface roughness and slope. J Wind Eng Ind Aerodyn 104–106:342–349

    Article  Google Scholar 

  • Carpenter P, Locke N (1999) Investigation of wind speeds over multiple two-dimensional hills. J Wind Eng Ind Aerodyn 83:109–120

    Article  Google Scholar 

  • Celik IB, Ghia U, Roache PJ, Freitas CJ, Coleman H, Raad PE (2008) Procedure for estimation and reporting of uncertainty due to discretization in CFD applications. ASME J Fluids Eng 130:1–4

    Google Scholar 

  • Chaudhari A, Vuorinen V, Agafonova O, Hellsten A, Hamalainen J (2014) Large-Eddy simulations for atmospheric boundary layer flows over complex terrains with applications in wind energy. In: Joint 11th World Congress on Computational Mechanics, the 5th European conference on computational mechanics, and the 6th European conference on computational fluid dynamics, Barcelona, Spain, pp 5205–5216

  • Cook NJ (1985) The designer’s guide to wind loading of building structures (Part 1), 1st edn. Butterworths, London

    Google Scholar 

  • Deaves DM, Harris RI (1978) A mathematical model of the structure of strong winds. Construction Industry Research and Information Association (CIRIA), Report 76, London

  • Diebold M, Higgins C, Fang J, Bechmann A, Parlange MB (2013) Flow over hills: a large-eddy simulation of the Bolund case. Boundary-Layer Meteorol 148:177–194

    Article  Google Scholar 

  • EN 1991-1-4 (2005) (English): Eurocode 1: actions on structures—part 1–4: general actions—wind actions [Authority: The European Union Per Regulation 305/2011, Directive 98/34/EC, Directive 2004/18/EC]

  • Ferreira AD, Silva MC, Viegas DX, Lopes AG (1991) Wind tunnel simulation of the flow around two dimensional hills. J Wind Eng Ind Aerodyn 38:109–122

    Article  Google Scholar 

  • Flay RGJ, Turner R, Revell M, Carpenter P, Cenek P, King AB (2012) Wind speed up over hills and complex terrain, and the risk to infrastructure. In: 18th Australasian fluid mechanics conference, 3–7 December, 2012, Launceston, Australia

  • Flay RGJ, Carpenter P, Revell M, Cenek P, Turner R, King A (2013a) Full-scale wind engineering measurements in New Zealand. In: The 8th Asia-Pacific conference on wind engineering, 10–14 December, 2013, Chennai, India

  • Flay RGJ, Turner R, Revell M, Carpenter P, Cenek P, King A (2013b) Wind speed-up measurements over Belmont Hill in complex terrain. In: 6th European and African conference on wind engineering, 7–13 July, Cambridge, UK

  • Flay RGJ, Nayyerloo M, King AB, Revell MJ (2015) Comparison of wind speed hill-shape multipliers calculated by seven wind loading standards with full-scale measurements. 17th Australasian Wind Engineering Society Workshop, 10–13 February, 2015, Wellington, New Zealand

  • Franke J, Hirsch C, Jensen AG, Krus HW, Schatzmann M, Westbury PS, Miles SD, Wisse JA, Wright NG (2004) Recommendations on the use of CFD in wind engineering. In: Proceedings of the international conference urban wind engineering and building aerodynamics, 5–7 May, Rhode-Saint-Genèse, Belgium

  • Franke J, Hellsten A, Schlunzen H, Carissimo BE (2007) Best practice guideline for the CFD simulation of flows in the urban environment. Cost action 732: quality assurance and improvement of microscale meteorological models, University of Hamburg, Meteorological Institute, Hamburg, Germany

  • Hargreaves DM, Wright NG (2007) On the use of the k–ɛ model in commercial CFD software to model the neutral atmospheric boundary layer. J Wind Eng Ind Aerodyn 95:355–369

    Article  Google Scholar 

  • Hewer FE (1998) Non-linear numerical model predictions of flow over an isolated hill of moderate slope. Boundary-Layer Meteorol 87:381–408

    Article  Google Scholar 

  • Hunt JR, Leibovich S, Richards KJ (1988) Turbulent shear flow over low hills. Q J R Meteorol Soc 114:1435–1470

    Article  Google Scholar 

  • Irwin HPAH (1981) A simple omnidirectional sensor for wind-tunnel studies of pedestrian-level winds. J Wind Eng Ind Aerodyn 7:219–239

    Article  Google Scholar 

  • Ishihara T, Hibi K (2002) Numerical study of turbulent wake flow behind a three-dimensional steep hill. Wind Struct 5(2–4):317–328

    Article  Google Scholar 

  • Ishihara T, Hibi K, Oikawa S (1999) A Wind tunnel study of turbulent flow over a three-dimensional steep hill. J Wind Eng Ind Aerodyn 83:95–107

    Article  Google Scholar 

  • Ishihara T, Fujino Y, Hibi K (2001) A wind tunnel study of separated flow over a two-dimensional ridge and a circular hill. Wind Eng 89:573–576

    Google Scholar 

  • Jackson PS, Hunt JCR (1975) Turbulent wind flow over a low hill. Q J R Meteorol Soc 101:929–955

    Article  Google Scholar 

  • Kaimal JC, Finnigan JJ (1994) Atmospheric boundary layer flows: their structure and measurement. Oxford University Press, New York

    Google Scholar 

  • Kim HG, Patel VC (2000) Test of turbulence models for wind flow over terrain with separation and recirculation. Boundary-Layer Meteorol 94:5–21

    Article  Google Scholar 

  • Kim HG, Lee CM, Lim HC, Kyong NH (1997) An experimental and numerical study on the flow over two-dimensional hills. J Wind Eng Ind Aerodyn 66:17–33

    Article  Google Scholar 

  • Launder BE, Spalding DB (1974) The numerical computation of turbulent flows. Comput Methods Appl Mech Eng 3:269–289

    Article  Google Scholar 

  • Liu Z, Ishihara T, Tanaka T, He X (2016) LES study of turbulent flow fields over a smooth 3-D hill and a smooth 2-D ridge. J Wind Eng Ind Aerodyn 153:1–12

    Article  Google Scholar 

  • Loureiro JB, Alho AT, Freire AP (2008) The numerical computation of near-wall turbulent flow over a steep hill. J Wind Eng Ind Aerodyn 96:540–561

    Article  Google Scholar 

  • Menter FR (1994) Two-equation eddy-viscosity turbulence models for engineering applications. Am Inst Aeronaut Astronaut 32(8):1598–1605

    Article  Google Scholar 

  • Miller C, Gibbons M, Beatty K, Boissonnade A (2013) Topographic speed-up effects and observed roof damage on Bermuda following Hurricane Fabian 2003. Weather Forecast 28:159–174

    Article  Google Scholar 

  • Moreira GA, Dos Santos AA, Do Nascimento CA, Valle RM (2012) Numerical study of the neutral atmospheric boundary layer over complex terrain. Boundary-Layer Meteorol 143:393–407

    Article  Google Scholar 

  • NBC (2015) National Building Code of Canada, National Research Council of Canada (NRC), Ottawa, Canada

  • O’Sullivan JP, Archer RA, Flay RGJ (2011) Consistent boundary conditions for flows within the atmospheric boundary layer. J Wind Eng Ind Aerodyn 99:65–77

    Article  Google Scholar 

  • Popinet S (2003) Gerris: a tree-based adaptive solver for the incompressible Euler equations in complex geometries. J Comput Phys 190:572–600

    Article  Google Scholar 

  • Raithby GD, Stubley GD, Taylor PA (1987) The Askervein Hill project: a finite control volume prediction of three-dimensional flows over the hill. Boundary-Layer Meteorol 39:247–267

    Article  Google Scholar 

  • Ramechecandane S, Gravdahl AR (2012) Numerical investigation on wind flow over complex terrain. Wind Eng 36(3):273–296

    Article  Google Scholar 

  • Richards PJ, Hoxey RP (1993) Appropriate boundary conditions for computational wind engineering models using the k–ɛ turbulence model. J Wind Eng Ind Aerodyn 46 & 47:145–153

    Article  Google Scholar 

  • Richards PJ, Norris SE (2011) Appropriate boundary conditions for computational wind engineering models revisited. J Wind Eng Ind Aerodyn 99:257–266

    Article  Google Scholar 

  • Richards PJ, Norris SE (2015) Appropriate boundary conditions for a pressure driven boundary layer. J Wind Eng Ind Aerodyn 142:43–52

    Article  Google Scholar 

  • Taylor PA, Gent PR (1974) A model of atmospheric boundary-layer flow above an isolated two-dimensional hill: an example of flow above gentle topography. Boundary-Layer Meteorol 7:349–362

    Article  Google Scholar 

  • Teunissen HW (1983) Wind tunnel and full scale comparisons of mean flow over an isolated low hill. J Wind Eng Ind Aerodyn 15:271–286

    Article  Google Scholar 

  • Troen I, Petersen EL (1989) European wind atlas. Risø National Laboratory, Roskilde

    Google Scholar 

  • User’s Guide—NBC 2015 Structural Commentaries (Part 4 of Division B), Commentary I: wind load and effects

  • Wilcox DC (1993) Turbulence modeling for CFD, 1st edn. DCW Industries, La Canada

    Google Scholar 

  • Wood N (1995) The onset of separation in neutral, turbulent flow over hills. Boundary-Layer Meteorol 76(137):164

    Google Scholar 

  • Wood N, Mason PJ (1993) The pressure force induced by neutral, turbulent flow over hills. Q J R Meteorol Soc 119:1233–1267

    Article  Google Scholar 

  • Yang Y, Gu M, Chen S, Jin X (2009) New inflow boundary conditions for modelling the neutral equilibrium atmospheric boundary layer in computational wind engineerring. J Wind Eng Ind Aerodyn 97:88–95

    Article  Google Scholar 

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Authors and Affiliations

  1. Department of Mechanical Engineering, University of Auckland, Auckland, 1142, New Zealand

    Amir A. Safaei Pirooz & Richard G. J. Flay

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  1. Amir A. Safaei Pirooz
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  2. Richard G. J. Flay
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Correspondence to Amir A. Safaei Pirooz.

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Safaei Pirooz, A.A., Flay, R.G.J. Comparison of Speed-Up Over Hills Derived from Wind-Tunnel Experiments, Wind-Loading Standards, and Numerical Modelling. Boundary-Layer Meteorol 168, 213–246 (2018). https://doi.org/10.1007/s10546-018-0350-x

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Keywords

  • Complex terrain
  • Horizontally-homogeneous boundary layer
  • Numerical modelling
  • Wind-loading standards and codes
  • Wind tunnel