Turbulence schemes have long been developed and examined for their accuracy and stability in variety of environments. While many flows work with disturbed turbulence intensity, models have rarely been tested to explore whether their accuracy withstands to augmented free stream turbulence intensity or declines to an erroneous solution. In present study turbulent intensity of flow stream of air, moving parallel to a flat plate, is augmented by means of locating a grid screen at a point at which Rex=2.5×105 and effect on downstream is studied. Depending on grid sizing, turbulent intensity is augmented from 0.4% to 6.6% for the whole flow at this cross section. Wind tunnel measurements provide the effect on downstream variables including velocity fluctuations in main stream and near the wall. Numerically, four most popular turbulence models are examined for similar physical case by more attention on turbulence penetration into flow field as well as into turbulent boundary layer of the flat plate. Numerical solutions of one equation Spalart-Almaras, two equations high Reynolds number , two equations Shear Stress Transport and anisotropy Reynolds Stress Models are compared to experimental measurements and results are discussed. Conclusion is made that despite accuracy these turbulence models believed to have, even in some difficult flow fields, they may fail to handle high intensity turbulent flows.

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