- Peter Kriznic, Synergetics Environmental Engineering
DOWNLOAD CONFERENCE PAPER - 59-peter-kriznic
The potential of urban wind power is gaining interest in the field of Environmentally Sustainable Design (ESD). However, the siting of wind turbines in the complex environment of the urban landscape becomes a problem for both architects and engineers. This paper discusses the use of computational fluid dynamic (CFD) modelling as a tool to aid the designer in evaluating where to locate such wind turbines.
CFD is able to provide a picture of the wind field near a proposed, or existing, building through the modelling and simulation of the building and surrounding environment at a fine scale. The simulated wind field around the building can be used to assess likely wind turbine sites in order to optimise exposure to prevailing wind directions, while gaining improvements in performance caused by proximity to the building. From the model results, it is possible to assess:
• Wind speed profiles with height over the top of the building for different wind directions to determine potential yield.
• Turbulence profiles with height over the top of the roof to in the siting of wind turbines within their design limits.
• The entire wind field over a building roof to optimise placement of wind turbines to maximise power generation once an appropriate height has been determined from speed and turbulence profiles.
• Any shielding of potential sites due to varying wind conditions by simulating numerous wind speeds and directions based on site-representative climactic statistics.
This paper outlines the modelling of a 100m tall building and the urban area in the immediate vicinity was using commercial CFD package FLUENT. The model consisted of an urban area with overall dimensions of approximately 2.9km x 2km. A mesh of approximately 1.6 million volumetric cells was used. A realisable k- RANS turbulence model was applied with appropriate atmospheric boundary conditions based on an assessment of the local meteorology and wind conditions.
The use of CFD as a tool to aid in the siting of wind turbines within the urban landscape offers the designer the potential to optimise their placement. As different wind directions and wind speeds can alter the exposure and suitability of a particular site, the information provided by CFD can be invaluable in selecting the type, height and location of a wind turbine in the urban landscape.