The unsteady wake of the Ahmed model has been investigated experimentally using time-accurate 5-hole and hot-wire probes and computationally using Exa PowerFLOW. The backlight angle was 25° which was chosen to be slightly below the critical angle observed computationally. The CFD results are similar to experimental results for backlight angles just below the critical angle (eg: 27.5°, 30°). Unsteady flow-field reconstruction of the experimental results and the CFD results both revealed a quasi-two-dimensional vortex-shedding type structure from the bottom of the model base. This results in a semi-periodic build up and collapse of the near wake and produces a symmetric oscillation in the strength and position of the rear pillar vortices. The period of this phenomenon corresponds to a Strouhal number of approximately 0.5 based on free-stream velocity and the square root of the model frontal area.


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    Title :

    The Ahmed Model Unsteady Wake: Experimental and Computational Analyses


    Additional title:

    Sae Technical Papers


    Contributors:

    Conference:

    SAE 2003 World Congress & Exhibition ; 2003



    Publication date :

    2003-03-03




    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




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