Large-eddy simulation of turbulent flow in a channel with rib roughness

Cui, Jie; Patel, V. C.; Lin, Ching‐Long

doi:10.1016/s0142-727x(03)00002-x

Cited by 166 publications

(77 citation statements)

References 24 publications

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“…4. A large value of u rms is found at the rib top, which is well in line with the simulated results by Cui et al [11]. In Fig.…”

Section: Overview Of the Flowsupporting

confidence: 92%

“…In this figure, only the quantities greater than 0.5 −u v max are demonstrated in order to highlight the region with large Reynolds shear stresses. It is clear that the maximum Reynolds shear stresses occur at the leading edge of the rib, which is in good agreement with Cui et al [11]. In the separated shear layer, the general trend is that the Reynolds shear stresses increase gradually with increasing distance from the rib.…”

Section: Overview Of the Flowsupporting

confidence: 90%

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Turbulent flow in a ribbed channel: Flow structures in the vicinity of a rib

Wang

Salewski

Sundén

2010

Experimental Thermal and Fluid Science

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PIV measurements are performed in a channel with periodic ribs on one wall. The emphasis of this study is to investigate the flow structures in the vicinity of a rib in terms of mean velocities, Reynolds stresses, probability density functions (PDF), and two-point correlations. The PDF distribution of u is bimodal in the separated shear layer downstream of the rib. The maximum Reynolds shear stresses occur at the leading edge of the rib. Based on quadrant analysis, it is found that ejection motions make a dominant contribution to the Reynolds shear stress in this region. Moreover, topology-based visualization is applied to the separation bubble upstream of the rib. Salient critical points and limit cycles are extracted, which gives clues to the physical processes occurring in the flow.

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“…4. A large value of u rms is found at the rib top, which is well in line with the simulated results by Cui et al [11]. In Fig.…”

Section: Overview Of the Flowsupporting

confidence: 92%

Section: Overview Of the Flowsupporting

confidence: 90%

Turbulent flow in a ribbed channel: Flow structures in the vicinity of a rib

Wang

Salewski

Sundén

2010

Experimental Thermal and Fluid Science

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“…Turbulent flows within and above regular obstacle arrays have been investigated by direct numerical simulations (Miyake et al 2001;Nagano et al 2004;Krogstad et al 2005;Coceal et al 2006), LES (Hanna et al 2002;Cui et al 2003;Kanda et al 2004b;Kanda 2006a), and RANS (Lien and Yee 2004;Hamlyn and Britter 2005). Results from LES applications (Kanda et al 2004b;Kanda 2006a) suggest some important physical aspects that are currently not emphasized in simpler CFD simulations: i.e., large dispersive momentum flux within the urban canopy layer due to a mean stream such as recirculation, intermittent urban canyon flow, non-persistent stream patterns, and longitudinally elongated streaks of low speed over building arrays with a scale an order of magnitude larger than individual buildings (Fig.…”

Section: Recent Technique a Simulation Techniquementioning

confidence: 99%

Progress in Urban Meteorology :A Review

Kanda

2007

Journal of the Meteorological Society of Japan

101

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This paper reviews the progress made in urban meteorology over the past few decades. The focus is on the impact of urban surfaces on the overlying atmosphere along the conventional meteorological frameworks. Section 1 details the difficulties in generalizing urban surfaces in a meteorological sense because of surface diversity, and considers whether conventional similarity law is applicable. Section 2 describes the characteristics of urban surfaces as the bottom boundary of the atmosphere and includes a discussion of land surface parameters and the resultant surface energy partitioning. Section 3 explains characteristics of the urban atmosphere, including temperature fields, local circulations and rainfall. Section 4 describes recent progress in numerical modeling and promising new technologies, thus revealing a possible future direction for urban meteorological studies.

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“…For a flow of given bulk Reynolds number, R, over two-dimensional roughness elements, the transition between d-and k-type roughness depends solely on the streamwise spacing of the elements. Many researchers have chosen to focus on square bar roughness to investigate the effect of spacing on turbulence structure and mean flow characteristics, both experimentally (Coleman, Nikora, McLean, & Schlicke, 2007;Djenidi, Antonia, Amielh, & Anselmet, 2008;Djenidi, Elavarasan, & Antonia, 1999;Krogstad, Andersson, Bakken, & Ashrafian, 2005;Okamoto, Seo, Nakaso, & Kawai, 1993;Roussinova & Balachandar, 2011) and numerically (Cui, Patel, & Lin, 2003;Ikeda & Durbin, 2007;Stoesser & Nikora, 2008;Stoesser & Rodi, 2004). Simpson (1973), Tani (1987), Jiminez (2004) and Coleman et al (2007) all proposed that the transition from d-to k-type roughness occurs at around l/k = 5, where l is the crest-to-crest bar spacing and k is the roughness height.…”

Section: Introductionmentioning

confidence: 99%

Free surface flow over square bars at intermediate relative submergence

McSherry

Chua

Stoesser

et al. 2018

Journal of Hydraulic Research

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Results from large-eddy simulations and complementary flume experiments of turbulent open channel flows over bed-mounted square bars at intermediate submergence are presented. Scenarios with two bar spacings, corresponding to transitional and k-type roughness, and three flow rates, are investigated. Good agreement is observed between the simulations and the experiments in terms of mean free surface elevations and mean streamwise velocities. Contours of simulated time-averaged streamwise, streamfunction and turbulent kinetic energy are presented and these reveal the effect of the roughness geometry on the water surface response. The analysis of the vertical distribution of the streamwise velocity shows that in the lowest submergence cases no logarithmic layer is present, whereas in the higher submergence cases some evidence of such a layer is observed. For several of the flows moderate to significant water surface deformations are observed, including weak and/or undular hydraulic jumps which affect significantly to the overall streamwise momentum balance. Reynolds shear stress, form-induced stress and form drag are analysed with reference to the momentum balance to assess their contributions to the total hydraulic resistance of these flows. The results show that form-induced stresses are dominant at the water surface and can contribute significantly to the overall drag, but the total resistance in all cases is dominated by form drag due to the presence of the bars.

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Large-eddy simulation of turbulent flow in a channel with rib roughness

Cited by 166 publications

References 24 publications

Turbulent flow in a ribbed channel: Flow structures in the vicinity of a rib

Turbulent flow in a ribbed channel: Flow structures in the vicinity of a rib

Progress in Urban Meteorology :A Review

Free surface flow over square bars at intermediate relative submergence

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