The Transitional Regime of Backward-Facing Step Flows

0372521 - ÚCHP 2012 RIV CZ eng C - Konferenční příspěvek (zahraniční konf.)
Tihon, Jaroslav - Pěnkavová, Věra - Havlica, Jaromír - Šimčík, Miroslav
The Transitional Regime of Backward-Facing Step Flows.
Proceedings. Liberec: Technical University of Liberec, 2011 - (Vít, T.; Dančová, P.; Novotný, P.), s. 1022-1039. ISBN 978-80-7372-784-0.
[Experimental Fluid Mechanics 2011. Jičín (CZ), 22.11.2011-25.11.2011]
Grant CEP: GA ČR GAP101/11/0806
Výzkumný záměr: CEZ:AV0Z40720504
Klíčová slova: bakward-facing step * flow instability * wall shear stress
Kód oboru RIV: CI - Průmyslová chemie a chemické inženýrství

The backward-facing step flow is investigated experimentally (electrodiffusion technique) and numerically (CFD software Fluent) at moderate Reynolds numbers achieved in a water channel. The direction sensitive sensors are used to measure the wall shear rate behind the step and detect the near-wall extent of different flow-recirculation regions. 2D numerical simulations provide additional information on the global flow rearrangement caused by the change of operational parameters (channel expansion ratios, inlet flow conditions). At the transitional flow regime, the near-wall flow exhibits an unsteady character with a high sensitivity to external low-frequency perturbations (intrinsic flow instability). The inlet pulsatile forcing is found to affect strongly the overall flow structure behind the step, resulting in the reattachment length reduction and the reverse flow intensification.
Trvalý link: http://hdl.handle.net/11104/0205821