Turbulence Measurements of Dye Concentration and Effects of Secondary Flow on Distribution in Open Channel Flows

Shiono, K.; Tao, Feng

doi:10.1061/(asce)0733-9429(2003)129:5(373)

Cited by 43 publications

(17 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It can be seen that the maximum magnitude of the secondary flow vectors is about 3% of the bulk streamwise velocity and the point of maximum secondary flow vector is located at y/H ≈ 0.26 and z/H ≈ 1.0. This conforms to previous findings reported by Nezu and Rodi [2], Tominaga et al [3], Naot and Rodi [4], Cokljat and Younis [5], Shi et al [6] and Shiono and Feng [7]. Note also the small vortex near the upper corner.…”

Section: Mean Flow Properties and Turbulence Structuressupporting

confidence: 93%

See 1 more Smart Citation

Direct numerical simulation of low Reynolds number flows in an open‐channel with sidewalls

Joung¹,

Choi

2009

Numerical Methods in Fluids

View full text Add to dashboard Cite

SUMMARYA direct numerical simulation of low Reynolds number turbulent flows in an open-channel with sidewalls is presented. Mean flow and turbulence structures are described and compared with both simulated and measured data available from the literature. The simulation results show that secondary flows are generated near the walls and free surface. In particular, at the upper corner of the channel, a small vortex called inner secondary flows is simulated. The results show that the inner secondary flows, counter-rotating to outer secondary flows away from the sidewall, increase the shear velocity near the free surface. The secondary flows observed in turbulent open-channel flows are related to the production of Reynolds shear stress. A quadrant analysis shows that sweeps and ejections are dominant in the regions where secondary flows rush in toward the wall and eject from the wall, respectively. A conditional quadrant analysis also reveals that the production of Reynolds shear stress and the secondary flow patterns are determined by the directional tendency of the dominant coherent structures.

show abstract

Section: Mean Flow Properties and Turbulence Structuressupporting

confidence: 93%

“…The boundary conditions for the velocity components are imposed on cbc and mbc, respectively. The matrix form of Equations (3) and (4) is factored into the block LU decomposition by Perot [20] as Dvinsky [21] Equation (5) is expressed as Au * = r+mbc (7) tDG p = Du * −cbc (8)…”

Section: Methodsmentioning

confidence: 99%

Direct numerical simulation of low Reynolds number flows in an open‐channel with sidewalls

Joung¹,

Choi

2009

Numerical Methods in Fluids

View full text Add to dashboard Cite

show abstract

“…Including all these studies some other studies on non prismatic compound channel and converging flood plain have also been conducted by researchers [e.g. (Salami, 1972), (Knight and Shiono, 1990), (Shiono and Feng, 2003), (Bousmar et al, 2004), (Nezu, 2005), (Proust et al, 2006), (Rezaei and Knight, 2009), (Baghalian et al, 2011), (Liu et al, 2012)]. …”

Section: Introductionmentioning

confidence: 99%

Flow Modeling in Symmetrically Narrowing Flood Plains

2015

View full text Add to dashboard Cite

Flooding situation in river is a complex phenomenon and affects the livelihood and economic condition of the region. The modelling of such flow is primary importance for a river engineers and scientists working in this field. As a result of topography changes along the open channels, designing the converging compound channel is an essential. Fluvial flows are strongly influenced by geometry complexity and large overall uncertainty on every single measurable property, such as velocity distribution on different sectional parameters like width ratio, aspect ratio and hydraulic parameter such as relative depth. The geometry selected for this study is that of a non-prismatic compound channel having converging flood plain. For the research work the parameters, the water depth, incoming discharge of the main channel and floodplains were varied. Continuous variation of channel geometry along the flow path associated with secondary currents makes the depth averaged velocity computation difficult. In this paper the variations of depth average velocities for five different sections in between the convergence region of the converging compound channel are compared by taking two different flow depth conditions. And also shear stress distribution at the walls and on the bed of two stage converging compound channel is calculated by doing experimentation in laboratory as bed shear forces are useful for the study of bed load transfer whereas wall shear forces presents a general view of channel migration pattern. Then the numerical method is applied to analyse the flow conditions in non-prismatic compound channel configurations, the results of calculations show good agreement with the experimental data. As numerical hydraulic models can significantly reduce costs associated with the experimental models, an effort has been made through the present investigation to determine the different flow characteristics of a converging compound channel such as velocity distribution, depth averaged velocity distribution, boundary shear etc. In this paper a complete three dimensional and two-phase CFD model for flow distribution in a converging compound channel is investigated by using Large Eddy Simulation (LES) model for solving the turbulence equation. This study aims to validate CFD simulations of free surface flow or open channel flow by using Volume of Fluid (VOF) method by comparing the data observed in hydraulics laboratory of the National Institute of Technology, Rourkela.

show abstract

“…PLIF was introduced in late 1970s and has been used to examine many types of flow, including flow in porous media (Dewey, 1976;Owen, 1976;Liu et al, 1977;Dimotakis et al, 1983;Montemagno and Gray, 1995;Rashidi et al, 1996;Crimaldi and Koseff, 2001;Pan and Meng, 2001;Fontenot and Vigil, 2002;Shiono and Feng, 2003;Stöhr et al, 2003;Webster et al, 2003;Arratia and Muzzio, 2004;Matsumoto et al, 2005;Troy and Koseff, 2005;Onishi and Komori, 2006;Ovdat and Berkowitz, 2006;Hsu et al, 2012). PLIF allows us to acquire undistorted cross-sectional images of blobs in complex porous media at a high temporal resolution.…”

Section: Introductionmentioning

confidence: 99%

Theoretical and experimental study of resonance of blobs in porous media

2012

View full text Add to dashboard Cite

We theoretically and experimentally investigated the frequency response of blobs in porous media to an oscillatory pressure difference. (The term blob refers to a connected liquid mass that occupies one or more pores.) To predict the frequency response analytically, we formulated a simple model pore system consisting of a blob in a capillary tube. This model accounts for the frequency-dependent viscous pressure drops in the blob and the surrounding liquid and for the dynamic capillary pressure that occurs due to contact line pinning. By using the planar laser-induced fluorescence technique, we visualized the dynamic response of blobs in porous media. As predicted by our theory, air and liquid blobs surrounded by an immiscible liquid exhibited resonance in a capillary tube. Furthermore, we showed, for the first time, that a liquid blob in a sphere-packing medium exhibits resonance.

show abstract

Turbulence Measurements of Dye Concentration and Effects of Secondary Flow on Distribution in Open Channel Flows

Cited by 43 publications

References 16 publications

Direct numerical simulation of low Reynolds number flows in an open‐channel with sidewalls

Direct numerical simulation of low Reynolds number flows in an open‐channel with sidewalls

Flow Modeling in Symmetrically Narrowing Flood Plains

Theoretical and experimental study of resonance of blobs in porous media

Contact Info

Product

Resources

About