Investigation On Spatial Distribution Of Mean Wind In Valley

The wind characteristics are the foundation of research on wind resistance, especially for the western mountain areas, studying on wind field characteristics in valley will provide an important reference to the design of wind resistance. At present, wind tunnel test and numerical simulation are the main means of studying on wind parameters. Although there are some researches and discussions of wind resistance regarding to bridges in mountainous are at home and abroad, there are few literature and datum about the actual measured weather, wind characteristics and wind resistance design. The canyon wind characteristics deserve further in-depth inquiry.This paper takes the canyon wind field of bridge site area as the research target. In order to study the effect on the canyon inner wind field causing by the form of the canyon and the change of gradient by the numerical simulation and wind tunnel test, abstract the canyon to simplified U valley canyon. By the numerical simulation, establishing geometric model of three dimensional, meshing to determine the calculation of basin, choosing proper boundary conditions and control parameters, determining the working conditions and measuring points. Calculated the average wind speed, analyzed the distribution characteristics of wind field and the contacts between different kinds of canyons, derived spatial distribution of average wind parameters inside the canyon. The speed and direction of the average wind in the valley model was measured by wind tunnel test and the results verified the validity and rationality of the numerical simulation method.Analyzing and fitting the results of the numerical calculation and wind tunnel test, referring to related documents and previous experiences, proposing the modified empirical formula of the design standard wind speed for bridge in canyon. Different modified empirical formulas of the design wind standard speed at the different height for bridge in canyon were proposed. The modified empirical formulas were checked and the results are satisfactory.