Etude expérimentale de la dispersion d'un scalaire passif dans le proche sillage d'un corps d'Ahmed

Abstract : This experimental work concerns the diffusion of heat downstream of a point source located at the Ahmed body base for slant angles a of 5°, 25° or 40°. This study has been carried out in air and in water at different Reynolds numbers. Laser Doppler Velocimetry (LDV), hot wire anemometry and cold wire thermometry have been used to measure velocity and temperature in the near wake ( ).
Characteristics of the velocity fields have been found to be strongly dependent on a when the Reynolds number increase. For a=25°, temperature and velocity measurements show in evidence the existence of a transition 2D-3D at a Reynolds number ReLc=2,7.104. Thermal fields revealed a high degree of complexity linked both to the complex nature of the dynamic field and the off axis location of injection. Scalar transport and mixing are analysed as a function of the rear slant angle a. The mixing problem has been studied by considering successively variations of maximum values of temperature excess, maximum intensity of the temperature variance and dissipation rate of temperature variance. These results allowed to determine the mixing time and to estimate the pollutant concentrations received by particular receptors (pedestrian close to a road or car driver).
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Submitted on : Wednesday, April 12, 2006 - 5:51:20 PM
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Kevin Gosse. Etude expérimentale de la dispersion d'un scalaire passif dans le proche sillage d'un corps d'Ahmed. Energie électrique. Université de Rouen, 2005. Français. ⟨tel-00012128⟩



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