Experimental research on kinematics of flows with high suspended solid concentration

Kereselidze, N. B.; Kutavaia, V.I.

doi:10.1080/00221689509498684

Cited by 9 publications

(3 citation statements)

References 5 publications

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“…Coleman's argument was supported by Parker and Coleman [1986] and Cioffi and Gallerano [1991]. However, Kreeselidze and Kutavaia [1995] and Lyn [1988] found that both Karman coefficient and wake strength vary with sediment concentration.…”

Section: Introductionmentioning

confidence: 95%

Turbulent transfer mechanism in sediment‐laden flow

Yang

2007

J. Geophys. Res.

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[1] Characteristics of turbulent flows in rivers can be significantly modified because of the presence of sediment particles and secondary currents/nonuniformity. This paper investigates why the measured vertical distributions of velocity deviate from the log law. In contrast to previous research that attributed the deviation to Richardson number only, this study demonstrates that like Reynolds shear stress (Àu 0 v 0 ), momentum flux (uv) caused by the nonzero wall-normal velocity v is also responsible for these deviations. Starting from Reynolds equations, this paper shows that the classical log law can be obtained only when v = 0; otherwise the velocity v results in the deviation. On the basis of experimental data available in the literature, this study shows that in an open channel, v is nonzero because of the coexistence of secondary currents and sediment and, subsequently, the Reynolds shear stress and streamwise velocity are affected. Equations for these interactions are obtained and solved numerically. The validity of the proposed model has been verified using experimental data, and good agreement between the predicted and observed profiles has been achieved.

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Section: Introductionmentioning

confidence: 95%

Turbulent transfer mechanism in sediment‐laden flow

Yang

2007

J. Geophys. Res.

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“…However, Lyn (1986Lyn ( ,1988 found that the von Karman constant K might decrease with sediment suspension even in the log-wake model. Kereselidze and Kutavaia (1995) deduced from their own experiments that both K and n vary with sediment suspension. Guo (1998) pointed out that both the log law and the log-wake law cannot satisfy the outer boundary condition at the outer boundary.…”

Section: Introductionmentioning

confidence: 98%

Turbulent velocity profiles in sediment-laden flows

Guo

Juliën

2001

Journal of Hydraulic Research

125

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A theoretical analysis shows that velocity profiles in sediment-laden flows are similar to those in clear water. The modified log-wake law, which is developed for clear water by Guo, is also valid in sediment-laden flows. The analysis of the effects of sediment suspension on turbulent kinetic energy and turbulent diffusion shows that: (1) sediment suspension increases mean flow energy loss; (2) sediment suspension weakens turbulent diffusion in the vertical direction and then increases velocity gradient; and (3) sediment suspension affects velocity profile in two ways: average concentration and density gradient. The comparison with narrow-channel laboratory data confirms the theoretical analysis and shows that: (1) the modified log-wake law agrees well with experimental data for sediment-laden flows; (2) both average concentration and density gradient reduce the von Karman constant; and (3) for a given width-depth ratio, sediment concen tration slightly increases the wake strength while density gradient has little effect on it. In addition, the modified log-wake law can reproduce experimental data where the maximum velocity occurs below the water surface. RÉSUMÉUne analyse théorique démontre la similitude des profils de vitesse avec ou sans transport de sediment. Les profils de vitesse logarithmiques avec coefficient de trainee sont done applicables pour les écoulements chargés de sediments. Cette loi permet de représenter les profils de vitesse avec maximum sous la surface libre. Les sediments en suspension: (1) augmentent les pertes d'énergie;(2) affaiblissent la diffusion turbulente verticale et augmentent Ie gradient de vitesse; et (3) affectent les profils de vitesse en raison de la concentration moyenne et du gradient de densité. La comparaison avec des données de laboratoire en canal étroit confirme que: (1) la loi logarithmique avec coefficient de trainee s'applique bien aux données expérimentales; (2) la concentration moyenne et Ie gradient de densité diminuent la constante de von Karman; et (3) pour un rapport largeur-profondeur donné, la concentration de sediments augmente légèrement Ie coefficient de trainee tandis que Ie gradient de densité exerce peu d'influence sur ce coefficient.

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“…By the study of the suspended load effect on the velocity profile in a flume with the two conditions of smooth and rough beds, Kereselidze and Kutavaia (1995) realized that the velocity in the smoothed bed flume is decreased close to the bed and increased near the free surface and therefore, the suspended load carrying flow average velocity in the smoothed bed flume may be smaller than, equal to or greater than the clear water flow velocity. While in the roughed bed flume, the suspended load carrying flow velocity is increased both close to the bed and near the free surface.…”

Section: Figure 2 a View Of A Side-channel Weirmentioning

confidence: 99%

Simulation of Flow Suspended Load in Weirs by Using Flow3D Model

Mehdi

Ghodousi

2015

Civ Eng J

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Sharp-crested weir and side-channel weirs can be considered among the control and flow-measuring structures which are greatly applicable in channels, dam spillways and other hydraulic structures. Discharge coefficient in these two types of weirs is affected by the structural geometry and the hydraulics of the flow. Suspended load is one of the main factors which may affect the hydraulics of the flow and consequently modify the flow discharge coefficient. Using different geometrical and hydraulic conditions, the discharge coefficient relation in sharp-crested and side channel weirs for the case of suspended load can be extracted. Flow3D numerical model is capable of precisely simulation the flow containing suspended and bed load in the main channel. The discharge coefficient equation is deduced and presented based on the Froude number, by numerical iterations. The numerical results reveal that the discharge coefficient in the two cases of clear water and the flow containing suspended load are totally different. At the same hydraulic load, the discharge coefficient in the case of existing suspended load is greater than the case of clear water; In addition, the discharge coefficient is reduced by increasing the Froude number in all cases with different load concentrations.

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Experimental research on kinematics of flows with high suspended solid concentration

Cited by 9 publications

References 5 publications

Turbulent transfer mechanism in sediment‐laden flow

Turbulent transfer mechanism in sediment‐laden flow

Turbulent velocity profiles in sediment-laden flows

Simulation of Flow Suspended Load in Weirs by Using Flow3D Model

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