TY - GEN
T1 - The impact of secondary mean vortices on turbulent separation in 3D Diffusers
AU - Von Terzi, Dominic
AU - Schneider, Hayder
AU - Bauer, Hans Jörg
PY - 2011
Y1 - 2011
N2 - In rectangular ducts with fully-developed turbulent flow, mean vortices in the corners form secondary flow patterns whose energy contents is orders of magnitude lower than that of the flow in the streamwise direction. In the present numerical experiments, it is demonstrated using Large Eddy Simulations (LES) that these Mean Secondary Vortices (MSV) exert a profound influence on flow separation in three-dimensional asymmetric diffusers following such a duct. By removing, enhancing or switching the sense of rotation of the MSV in the inlet duct of two diffusers the shape, location and extent of separation zones farther downstream were drastically altered and, hence, the performance of the device. These results provide an explanation why eddy-viscosity based Reynolds-Averaged Navier-Stokes (RANS) models, that inherently cannot account for MSV, fail in predicting even the location of the separated flow in such diffusers.
AB - In rectangular ducts with fully-developed turbulent flow, mean vortices in the corners form secondary flow patterns whose energy contents is orders of magnitude lower than that of the flow in the streamwise direction. In the present numerical experiments, it is demonstrated using Large Eddy Simulations (LES) that these Mean Secondary Vortices (MSV) exert a profound influence on flow separation in three-dimensional asymmetric diffusers following such a duct. By removing, enhancing or switching the sense of rotation of the MSV in the inlet duct of two diffusers the shape, location and extent of separation zones farther downstream were drastically altered and, hence, the performance of the device. These results provide an explanation why eddy-viscosity based Reynolds-Averaged Navier-Stokes (RANS) models, that inherently cannot account for MSV, fail in predicting even the location of the separated flow in such diffusers.
UR - http://www.scopus.com/inward/record.url?scp=84855484045&partnerID=8YFLogxK
U2 - 10.1007/978-3-642-15748-6_26
DO - 10.1007/978-3-642-15748-6_26
M3 - Conference contribution
AN - SCOPUS:84855484045
SN - 9783642157479
T3 - High Performance Computing in Science and Engineering 2010 - Transactions of the High Performance Computing Center, Stuttgart, HLRS 2010
SP - 339
EP - 352
BT - High Performance Computing in Science and Engineering 2010 - Transactions of the High Performance Computing Center, Stuttgart, HLRS 2010
PB - Springer
T2 - 13th Annual Results and Review Workshop on High Performance Computing in Science and Engineering, HLRS 2010
Y2 - 4 October 2010 through 5 October 2010
ER -