Wind tunnel tests of effects of atmospheric stability on turbulent flow over a three-dimensional hill

Takahashi, Takéo; Kato, Shinsuke; Murakami, Shuzo; Ooka, Ryozo; Yassin, Mohamed F.; Kono, Ryohei

doi:10.1016/j.jweia.2004.11.003

Cited by 39 publications

(15 citation statements)

References 5 publications

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“…These results are qualitatively similar to the wind tunnel observations of thermally stratified flow over a hill reported by Takahashi et al (2005). This effect too is partially reflected in the calculation of re-attachment length, where the shear stress on the wall is zero, for the different thermally stratified atmospheres, shown in Table 7-9.…”

Section: Resultssupporting

confidence: 87%

“…The CFD models, modified to account for gravity effects, therefore need to be validated against experimental data. These measurements were obtained in the thermally stratified wind tunnel of the University of Tokyo, using three-dimensional laser Doppler anemometry (Takahashi et al 2005). The model is an axisymmetric cosine shaped hill of scale 1/1000, with the height h defined in terms of the radius r by:…”

Section: Cfd Simulation Of Flow Over a Cosine Hillmentioning

confidence: 99%

“…The boundary conditions for the velocity and turbulent kinetic energy were derived for the results presented by Takahashi et al (2005) for the incident flow in the wind tunnel, and the results of the flow field around the hill model for the mean streamwise velocity and the turbulent kinetic energy were used for comparison to the CFD results.…”

Section: Cfd Simulation Of Flow Over a Cosine Hillmentioning

confidence: 99%

See 2 more Smart Citations

CFD investigation of the atmospheric boundary layer under different thermal stability conditions

Pieterse

Harms

2013

Journal of Wind Engineering and Industrial Aerodynamics

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Section: Resultssupporting

confidence: 87%

Section: Cfd Simulation Of Flow Over a Cosine Hillmentioning

confidence: 99%

Section: Cfd Simulation Of Flow Over a Cosine Hillmentioning

confidence: 99%

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CFD investigation of the atmospheric boundary layer under different thermal stability conditions

Pieterse

Harms

2013

Journal of Wind Engineering and Industrial Aerodynamics

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“…A hill is a simple case of terrain inhomogeneity that alters the large-scale structure of the incoming turbulence (Tampieri et al 2003) and sheds large-scale vortices (as compared to the rotor diameter) able to leave a signature on the rotor angular velocity time history and statistics (Howard and Chamorro 2013). The effect of terrain complexity on the large-scale structures of the ABL, however, strongly depends on the local thermal stability regime (Takahashi et al 2005), e.g. when topographical perturbations induce large-scale instabilities (Kelvin-Helmholtz and internal waves) in strongly stratified flows.…”

Section: Introductionmentioning

confidence: 99%

A Comparative Analysis on the Response of a Wind-Turbine Model to Atmospheric and Terrain Effects

Howard

Chamorro

Guala

2015

Boundary-Layer Meteorol

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In a series of wind-tunnel experiments conducted at the St. Anthony Falls Laboratory, a wind-turbine model was exposed to three different thermal regimes (neutral, weakly stable and weakly convective flows) in three simple arrangements relevant to wind-farm applications: single turbine in the boundary-layer, aligned turbine-turbine, and an upwind three-dimensional sinusoidal hill aligned with the turbine. Results focus on the spatial evolution of large-scale motions developing over the different thermal and topographic boundary conditions, and on their influence on the mean and fluctuating angular velocity of the turbine rotor. As compared to the single turbine case, both the upwind hill and turbine caused a reduction in the mean angular velocity regardless of the thermal regime; the turbine angular velocity fluctuations always decreased with a turbine upwind, which depleted the energy of the large structures of the flow; however such fluctuations decreased (increased) under stably stratified (convective) conditions when the hill was present. Pre-multiplied spectra of the rotor angular velocity and two-point correlation contours of the streamwise velocity component confirmed a non-trivial link between thermal stratification and terrain complexity. It is inferred that the thermal effects occurring in the three different boundary-layer regimes modulate the spanwise motion of the hill wake and define whether the hill shelters or exposes the turbine to enhanced large-scale energetic motions.

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“…This has introduced different and interesting multi-physics challenges and in some cases extensive and complex topography (Wood [5]). The use of CFD in the natural environment is increasing (Baker [6]), but it has often been limited to idealised situations such as isolated hills or dunes without vegetation or sediment transport (Lubitz and White [7] and Takahashi et al [8]). These cases have led to important advancements in the application of CFD understanding of wind flow speedup (Hesp et al [9]) but there has been little extension of this approach to more realistic landscapes.…”

Section: Computational Fluid Dynamics (Cfd)mentioning

confidence: 99%

Three-dimensional flow simulation over a complex sand dune system

Wakes

Maegli

Dickinson

et al. 2008

WIT Transactions on the Built Environment

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Invasive, non-indigenous plants such as marram grass (Ammophila arenaria) have been used extensively in New Zealand to stabilise dune systems but this activity has resulted in a loss of indigenous biodiversity as well as significant changes in dune morphology. The restoration of natural dune systems has become a focus for some of the least modified coastal regions with associated concerns as to what effect marram grass eradication or other such interventions may have on dune stability.An ongoing project at Mason Bay, Stewart Island, New Zealand has examined all aspects of marram grass invasion and eradication. This paper concentrates on the initial three-dimensional CFD model that simulates the wind flow over this complex dune system compared with field data with detailed LIDAR data used to recreate the complex topography of the dune system. Various modelling options are assessed for their accuracy in emulating the field data. The topography was found to greatly affect the results, making it difficult to determine the actual wind flow pattern over such a complex system. The effectiveness of three-versus two-dimensional CFD modelling is therefore discussed in terms of accuracy, practicality and complexity and the feasibility for practical planning purposes is also explored.

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Wind tunnel tests of effects of atmospheric stability on turbulent flow over a three-dimensional hill

Cited by 39 publications

References 5 publications

CFD investigation of the atmospheric boundary layer under different thermal stability conditions

CFD investigation of the atmospheric boundary layer under different thermal stability conditions

A Comparative Analysis on the Response of a Wind-Turbine Model to Atmospheric and Terrain Effects

Three-dimensional flow simulation over a complex sand dune system

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