An Evaluation of the Discrete Vortex Method as a Model for the Flow Past a Flat Plate Normal to the Flow with a Large Wake Splitter Plate
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A discrete vortex model of the Biot-Savart type is proposed for the flow past a flat plate normal to the flow with a long wake splitter plate in its plane of symmetry. A very basic model, incorporating potential vortices, removal of vortices far downstream and near the wall and a two-equation model for the introduction of new vortices into the flow field did not allow calculations beyond the level of determining the drag of the plates.
Incorporating a more elaborate Rankine vortex model and a temporal decrease of the circulation of the individual vortices produced consistent results for the pressure and the velocity field. The qualitative agreement with experiments was quite good since experimental results were used to select empirical parameters, the quantitative agreement was acceptable only for the time mean values. For the Reynolds stresses the quantitative agreement was as bad as was expected from the calculation of other authors.
A simulation of the creation of vorticity of opposite sign at walls showed, that this is only one of the main physical effects which were simulated by temporal decrease of circulation and not the cause for the discrepancy between numerical and wind-tunnel results. The physical effects of three-dimensional vortex-vortex interaction and three-dimensional transport of vorticity cannot be modelled in the simple two-dimensional model used here and are the probable causes for the inability of discrete vortex model to predict turbulent intensities and correlations.
KeywordsTurbulent Intensity Flat Plate Quantitative Agreement Splitter Plate Vortex Method
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