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Christian Stemmer

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Conference paper (2011) - Zhen Li Chen, Antoine Devesa, Michael Meyer, Eric Lauer, Stefan Hickel, Christian Stemmer, Nikolaus A. Adams
In order to perform Implicit Large Eddy Simulation (ILES) on complex geometries at high Reynolds numbers, a wall model based on the simplified Thin Boundary Layer Equations (TBLE) is designed in the framework of ILES with a cut-cell finite-volume immersed boundary method. This wall model is validated for turbulent channel flow at friction Reynolds number up to Reτ = 2,000 on very coarse grids. The results compared with DNS and LES without wall model show that the wall model has the potential to improve the mean velocity in the outer flow region well at high Reynolds number. The wall model is applied to a complex converging diverging channel flow at Reynolds number Re = 7,900 on very coarse meshes. Improved mean velocities and Reynolds stresses are obtained, which shows that the wall model has the ability to perform ILES on complex geometries at high Reynolds numbers. ...
Book chapter (2010) - Zhenli Chen, Antoine Devesa, Stefan Hickel, Christian Stemmer, Nikolaus A. Adams
In order to perform implicit Large Eddy Simulation (LES) of high Reynolds number wall-bounded flows, a wall model based on simplified Thin Boundary Layer Equations (TBLE) is designed and applied to turbulent channel flow for a wide range of friction Reynolds numbers up to Re τ =20,000. The prediction capability of the employed wall model concerning mean velocities and Reynolds stresses is satisfactory, even on very coarse LES grids. The coupling position between the simplified TBLE model and the LES should be located at the bottom of the logarithmic region. The grid resolution requirement depends mainly on the embedded TBLE grids and is only weakly dependent on the Reynolds number. ...