The Effect of Inlet Pulsations on the Backward-Facing Step Flow

0341764 - ÚCHP 2011 RIV FR eng J - Journal Article
Tihon, Jaroslav - Pěnkavová, Věra - Pantzali, M.
The Effect of Inlet Pulsations on the Backward-Facing Step Flow.
European Journal of Mechanics B-Fluids. Roč. 29, č. 3 (2010), s. 224-235. ISSN 0997-7546. E-ISSN 1873-7390
R&D Projects: GA ČR GA101/04/0745; GA ČR GA104/08/0428
Grant - others:HPMT(XE) CT/2000/00074
Institutional research plan: CEZ:AV0Z40720504
Keywords : flow separation and reattachment * backward-facing step * wall shear stress
Subject RIV: CI - Industrial Chemistry, Chemical Engineering
Impact factor: 1.068, year: 2010

This experimental study of backward-facing step flow is focused on the transient flow regime (Reh is ranging from 30 to 1800). An unsteady flow pattern with several regions of flow separation downstream the step is investigated in a water channel with the most common expansion geometry (ER=2). The electrodiffusion technique of wall shear rate measurements is applied to recognize the flow structure behind the step. The sliding step configuration enables sufficient mapping of the near-wall flow region even if only two direction-sensitive probes are flush-mounted into the downstream channel walls. The wall shear rate profiles (at bottom and roof) are obtained under steady and pulsatile (frequency up to 3 Hz) flow conditions at the inlet. The inlet flow pulsations affect strongly the overall flow structure behind the step. Up to 80% reduction of the reattachment length is achieved by applying flow pulsations at the most effective frequency.
Permanent Link: http://hdl.handle.net/11104/0184648