Abstract

The turbulent flow fields in a static and rotating ribbed channel are investigated by mean of wall-resolved compressible LES. This approach has been previously validated in a squared ribbed channel based on an experimental database from Von Karman Institute. LES results prove to reproduce differences induced by buoyancy in the near rib region and resulting from adiabatic or anisothermal flows under rotation as well as the turbulence increase (decrease) around the rib in destabilizing (stabilizing) rotation of the ribbed channels. This paper investigates the spatial development of the flow along the channel and its potential impact on secondary flow structures. Results on the adiabatic static case exhibits two contra-rotating structures close to the lateral walls of the channel induced by transversal pressure difference created by the ribs. When considering the stabilizing rotating case, two additional contra-rotating structures also develop along the channel from the en- trance close to the low-pressure wall (rib-mounted side). Gortler vortices also appear on the pressure wall (opposite to the rib-mounted side). In the destabilizing rotating case, these two types of secondary structures are found to co-exist and their migration in the channel is significantly different due to the presence of the ribs on the pressure side. Finally, it is shown that heat transfer affects only marginally the static and stabilized cases while it changes more significantly the flow organization in the destabilizing case mainly because of enhanced heat transfer and increased buoyancy force effects.

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