Large eddy simulation of separation control over a backward-facing step flow by suction

Zheng, Chao; Yao-chun, Zhang; Zhang, Wenyuan

doi:10.1080/10618562.2011.558010

Cited by 9 publications

(2 citation statements)

References 29 publications

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“…By configuring backward-facing steps to form d -type ribs on a porous surface, the cross-step models created persistent vortices in zone 2 that were sustained as water entered the slot and exited through the mesh. Suction along the bottom of the downstream wall in a backward-facing step has been used as an active control technique to reduce the disruptive effects of flow separation and recirculation in engineering applications with nonporous channels 37 38 . In contrast, our cross-step design harnessed the separated shear layer and the recirculation region to prevent clogging of the porous mesh during filtration.…”

Section: Discussionmentioning

confidence: 99%

Fish mouths as engineering structures for vortical cross-step filtration

et al. 2016

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Suspension-feeding fishes such as goldfish and whale sharks retain prey without clogging their oral filters, whereas clogging is a major expense in industrial crossflow filtration of beer, dairy foods and biotechnology products. Fishes' abilities to retain particles that are smaller than the pore size of the gill-raker filter, including extraction of particles despite large holes in the filter, also remain unexplained. Here we show that unexplored combinations of engineering structures (backward-facing steps forming d-type ribs on the porous surface of a cone) cause fluid dynamic phenomena distinct from current biological and industrial filter operations. This vortical cross-step filtration model prevents clogging and explains the transport of tiny concentrated particles to the oesophagus using a hydrodynamic tongue. Mass transfer caused by vortices along d-type ribs in crossflow is applicable to filter-feeding duck beak lamellae and whale baleen plates, as well as the fluid mechanics of ventilation at fish gill filaments.

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Section: Discussionmentioning

confidence: 99%

Fish mouths as engineering structures for vortical cross-step filtration

et al. 2016

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“…Also, carried out an experimental study on turbulent flow characteristics in submerged plane wall jets subjected to injection and suction from the wall. Zheng et al (2011) investigated separation control over a backward-facing step flow by continuous suction using the turbulence model of large eddy simulation numerically. In addition, jet injection or jets form one of the boundary layer control techniques that generate enough kinetic energy in the boundary layer to control flow separation and decrease the downflow strength as well as the horseshoe vortex effect.…”

Section: Introductionmentioning

confidence: 99%

Reduction of pier scour using bed suction and jet injection

Soltani-Gerdefaramarzi

Afzalimehr

Chiew

et al. 2014

Proceedings of the Institution of Civil Engineers - Water Manag

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The influence of a combined system of jet injection through the pier and bed suction on the reduction of local scour around a circular pier was investigated in a laboratory flume. Experiments were conducted for two water depths (10 . 5 and 28 cm) under 1-jet and 3-jet injection and different angles between the jets, with bed suction rate Q s /Q 0 2%, in turbulent flow and clear-water scouring conditions. The results show that the bed suction modifies the effect of jet scouring and reduces the local scour and sediment transport at the pier (36% for scour depth, 25 and 42% for the area and volume of scour hole). The maximum reduction of the scour depth was about 50% (about 20, 39 and 39% for the area, volume and the upstream slope of the scour hole respectively) in the best configurations for a combined countermeasure.

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