Abstract
A new hybrid RANS-LES method of DDES-type for flows over airfoil sections with small/incipient separation is presented. It alters the RANS-LES switch based on the function f d in the DDES formulation. Regions of attached boundary layer flow, the separation point and the subsequent region of separation are detected by sensors. They are based on a combination of algebraic properties of the mean velocity profiles in wall-normal direction and of integral boundary layer quantities, namely the shape factor H 12. While the RANS length scale l RANS is used in attached boundary layers, the LES length scale C DESΔ is used in regions of separated flow. In particular, thin regions of (incipiently) separated flow are treated in LES mode except for a near-wall region where l RANS is used. Moreover, in the vicinity of the separation point or in the entire separation region, a stochastic SGS model can be used as a simple method to force the generation of turbulent content.
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© 2013 Springer-Verlag Berlin Heidelberg
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Knopp, T., Probst, A. (2013). An Algebraic Sensor for the RANS-LES Switch in Delayed Detached-Eddy Simulation. In: Dillmann, A., Heller, G., Kreplin, HP., Nitsche, W., Peltzer, I. (eds) New Results in Numerical and Experimental Fluid Mechanics VIII. Notes on Numerical Fluid Mechanics and Multidisciplinary Design, vol 121. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-35680-3_54
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DOI: https://doi.org/10.1007/978-3-642-35680-3_54
Publisher Name: Springer, Berlin, Heidelberg
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