Comparison of turbulent flow over solid and porous structures mounted on the bottom of a rectangular channel

Leu, Jan-Mou; Chan, Hsun-Chuan; Chu, M.

doi:10.1016/j.flowmeasinst.2008.05.001

Cited by 41 publications

(24 citation statements)

References 13 publications

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“…Chan et al (2010) numerically studied turbulent flow over a porous rib by using the Pedras and de Lemos (2001b) model. Their predictions were in a good agreement with the experimental study of Leu et al (2008). Kuwata et al (2014) used their multi-scale k − ε model to investigate turbulent flow around a porous rib mounted on a porous layer that half filled a channel.…”

Section: Introductionsupporting

confidence: 55%

“…The results showed that the minimum recirculation zone and best heat transfer augmentation was obtained with the largest inclination angle. Leu et al (2008) performed an experimental investigation of turbulent flow in a channel with a rib mounted at the bottom by using the Acoustic Doppler velocimeter (ADV). Ribs of three different structures were examined, whose geometric porosities were 0%, 34.9%, and 47.5%.…”

Section: Introductionmentioning

confidence: 99%

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Improved Eddy-Viscosity Modelling of Turbulent Flow around Porous–Fluid Interface Regions

2019

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The RANS modelling of turbulence across fluid-porous interface regions within ribbed channels has been investigated by applying double (both volume and Reynolds) averaging to the Navier-Stokes equations. In this study turbulence is represented by using the Launder and Sharma (1974) low-Reynolds number k − ε turbulence model, modified via proposals by either Nakayama and Kuwahara (2008) or Pedras and de Lemos (2000), for extra source terms in turbulent transport equations to account for the porous structure. One important region of the flow, for modelling purposes, is the interface region between the porous medium and clear fluid regions. Here, corrections have been proposed to the above porous drag/source terms in the k and ε transport equations that are designed to account for the effective increase in porosity across a thin near-interface region of the porous medium, and which bring about significant improvements in predictive accuracy. These terms are based on proposals put forward by Kuwata and Suga (2013), for second-moment closures. Two types of porous channel flows have been considered. The first case is a fully developed turbulent porous channel flow, where the results are compared with DNS predictions obtained by Breugem et al. (2006) and experimental data produced by Suga et al. (2010). The second case is a turbulent solid/porous rib channel flow to examine the behaviour of flow through and around the solid/porous rib, which is validated against experimental work carried out by Suga et al. (2013). Cases are simulated covering a range of porous properties, such as permeability and porosity. Through the comparisons with the available data, it is demonstrated that the extended model proposed here shows generally satisfactory accuracy, except for some predictive weaknesses in regions of either impingement or adverse pressure gradients, associated with the underlying eddy-viscosity turbulence model formulation.

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Section: Introductionsupporting

confidence: 55%

Section: Introductionmentioning

confidence: 99%

Improved Eddy-Viscosity Modelling of Turbulent Flow around Porous–Fluid Interface Regions

2019

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“…Plant permeability, arising from multiple or bifurcated stems, may probably not be a direct adaptation to flood stresses, but systematic fluid mechanical lab studies suggest that an increasing permeability leads to an increased amount of bleed flow (i.e. flow penetrating the obstacle), weakening of the horseshoe vortex and increasing length of the recirculation zone in the obstacle wake (Castro, 1970;Dong et al, 2008;Leu et al, 2008). The latter denotes a leeside region, where those currents that have detached from the obstacle exhibit a reversal flow behaviour, because of low pressures in the central near wake.…”

Section: Permeabilitymentioning

confidence: 99%

Influence of inclination and permeability of solitary woody riparian plants on local hydraulic and sedimentary processes

Euler¹,

Zemke

Rodrigues

et al. 2013

Hydrol. Process.

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The role of solitary woody riparian plants with respect to local erosion and deposition of sediments is investigated. A focus is laid on the characteristics ‘inclination’ and ‘permeability’ of the plant's projected frontal area. Therefore, two experimental studies using cylindrical obstacles were carried out in a laboratory flume, one aiming at inclination, the other at permeability. The first series revealed that the total amount of mobilized sediment around the cylinder on average decreased by 8–10% per 5° increasing inclination in streamwise direction. Locations of maximum scour depth simultaneously shifted downstream. A horseshoe vortex system, causing the frontal and lateral scouring, ceased to exist below inclinations of 25–30°. The second series revealed that with increasing permeability, frontal scour incision is delayed, and the eroded sediment volume is significantly reduced. With permeable obstacles, two system states were observed: first, frontal scouring with leeside deposition at higher flow velocities and, second, moderate leeside scouring at lower flow velocities. For up‐scaling and comparison, a field study focussing on fluvial obstacle marks at poplars and willows in secondary channels of the River Loire was additionally conducted. A modified analytical model enabled us to quantify the amount of deposited sediments leeside of the plants. Leeside sediment ridges are significantly stabilized and have a higher preservation potential when covered by pioneer vegetation. Under such conditions, they may indeed induce the development of stable islands. Eventually, ‘sediment ridge width’ turned out to be a suitable indicator for leeside deposited sediment volume, irrespective of spatial scale. Copyright © 2012 John Wiley & Sons, Ltd.

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“…(1957. Do wyników tych odnosi się większość późniejszych badań zarówno dotyczących określenia wartości współczynnika wydatku (Clemmens, Replogle i Rein ink, 1990;Salmasi, Poorescandar, Dalir i Zadeh, 2011;Hoseini i Afshar, 2014;Bajkowski, 2016), jak i układu zwierciadła wody (Leu, Chan i Chu, 2008;Goodarzi, Farhoudi i Shokri, 2012). Najnowsze badania układu strumienia przelewów o różnych kształtach przekroju poprzecznego, prostoliniowych i rozwiniętych w planie opisał Emiroglu (2010).…”

Section: Wstępunclassified

Przelew trapezowy o pionowej ścianie wlotowej

Bajkowski

2018

ACTA SCIENTIARUM POLONORUM - Architectura Budownictwo

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Comparison of turbulent flow over solid and porous structures mounted on the bottom of a rectangular channel

Cited by 41 publications

References 13 publications

Improved Eddy-Viscosity Modelling of Turbulent Flow around Porous–Fluid Interface Regions

Improved Eddy-Viscosity Modelling of Turbulent Flow around Porous–Fluid Interface Regions

Influence of inclination and permeability of solitary woody riparian plants on local hydraulic and sedimentary processes

Przelew trapezowy o pionowej ścianie wlotowej

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