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Numerical Investigation of a Drag Reduction Device Applied to the Ahmed Body

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In this paper, a new technique of drag reduction around a simplified car body called the Ahmed body is introduced. A conduit has been perforated in this body. The purpose of this conduit is bringing part of airflow from the body’s front to be injected in its rear end where the recirculation occurs. In this study, a numerical model of a turbulent flow around a two–dimensional then three–dimensional body has been developed. Numerical simulations have been performed using the computational fluid dynamics software ANSYS Fluent. For the 2D case, series of numerical simulations have been performed. In these simulations, the conduit position relative to the body’s lower slant edge has been modified. For the position with minimum drag, the effect of narrowing the conduit exit has been tested. Finally, the effect of narrowing the conduit exit has been studied. For the 3D case, the effect of changing dimensions of a rectangular conduit and its position from the body’s lower slant edge have been studied. For the position with lower drag, the effect of narrowing the conduit exit has been studied. The 2D and 3D results show that in some conduit configurations, drag could be reduced.
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Ahmed Body; Conduit; Drag; Reduction; Turbulent Flow; ANSYS Fluent

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