Application of Several Depth-Averaged Turbulence Models to Simulate Flow in Vertical Slot Fishways

Cea, Luís; Pena, Luis; Puertas, Jerónimo; Vázquez-Cendón, M. Elena; Peña, Enrique

doi:10.1061/(asce)0733-9429(2007)133:2(160)

Cited by 67 publications

(56 citation statements)

References 23 publications

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“…These results differ slightly from those by Cea et al (2007) who found no differences for Manning's coefficients ranging between n g = 0 (no friction) and n g = 0.03 s/m 1/3 . The present study confirmed that bed friction does not play an important role for this type of flow.…”

Section: Results and Discussion Manning's Roughness Coefficientcontrasting

confidence: 99%

“…For weak shear layers and axisymmetric jets some of the constants have to be replaced by functions (Rodi, 1993). Another problem of eddy viscosity models is that for large values of eddy viscosity, Boussinesq's assumption can imply negative normal Reynolds stresses which is physically incorrect (Cea et al, 2007;Chorda et al, 2010). In order to improve the results for such cases, different limiters have been proposed by Menter (1993) and Durbin (1996).…”

Section: Smagorinsky Turbulence Modelmentioning

confidence: 99%

“…So far different geometries of VSF with 5-15% longitudinal slope have been studied on scale models (Liu et al, 2006;Puertas et al, 2004;Rajaratnam et al, 1986;Rajaratnam et al, 1992;Tarrade et al, 2008), as well as with numerical programs (Bermúdez et al, 2010;Cea et al, 2007;Chorda et al, 2010;Violeau, 2012). The results of these studies showed that generally two flow patterns occur.…”

Section: Velocity Fieldmentioning

confidence: 99%

“…geometry of the pool Rajaratnam et al, 1992). Once a suitable pool design has been found, a vertical slot fishway will work effectively for a wide range of discharges (Clay, 1995) because the flow pattern is relatively insensitive to variations of the total flow (Cea et al, 2007). The flow pattern in the pools is of great importance in order to guide the fish through the fishway.…”

Section: Introductionmentioning

confidence: 99%

“…Larger vertical velocities may occur only in the slot region and depend mainly on the slope of the fishway, more precisely on the difference in water levels between two adjacent pools. The observation, that the flow in VSF is mostly 2-D in nature, opens up the possibility of using a depth-averaged shallow water model in order to compute the flow field in VSF (Cea et al, 2007). Previous numerical studies by Cea et al (2007), Chorda et al (2010) and Violeau (2012) have used this approach to study flow characteristics such as velocities, water surface elevations, local vorticity, turbulent kinetic energy per unit mass k, and energy dissipation rate per unit mass ε.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Numerical and physical model study of a vertical slot fishway

Bombač¹,

Novak

Rodic³

et al. 2014

Journal of Hydrology and Hydromechanics

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This paper presents the results of an experimental and numerical study of a vertical slot fishway (VSF). A 2-D depth-averaged shallow water numerical model PCFLOW2D coupled with three different turbulent models (constant eddy viscosity, Smagorinsky and k -ε) was used. A detailed analysis of numerical parameters needed for a correct simulation of the phenomenon was carried out. Besides the velocity field, attention was paid to important hydraulic parameters such as maximum velocity in the slot region and energy dissipation rate ε in order to evaluate the performance of VSF. A scaled physical hydraulic model was built to ensure reliable experimental data for the validation of the numerical model. Simulations of variant configurations of VSF showed that even small changes in geometry can produce more fishfriendly flow characteristics in pools. The present study indicates that the PCFLOW2D program is an appropriate tool to meet the main demands of the VSF design.

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Section: Results and Discussion Manning's Roughness Coefficientcontrasting

confidence: 99%

Section: Smagorinsky Turbulence Modelmentioning

confidence: 99%

Section: Velocity Fieldmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Numerical and physical model study of a vertical slot fishway

Bombač¹,

Novak

Rodic³

et al. 2014

Journal of Hydrology and Hydromechanics

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Unstructured finite volume discretization of two‐dimensional depth‐averaged shallow water equations with porosity

Cea¹,

Vázquez-Cendón²

2009

Numerical Methods in Fluids

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SUMMARYThis paper deals with the numerical discretization of two-dimensional depth-averaged models with porosity. The equations solved by these models are similar to the classic shallow water equations, but include additional terms to account for the effect of small-scale impervious obstructions which are not resolved by the numerical mesh because their size is smaller or similar to the average mesh size. These small-scale obstructions diminish the available storage volume on a given region, reduce the effective cross section for the water to flow, and increase the head losses due to additional drag forces and turbulence. In shallow water models with porosity these effects are modelled introducing an effective porosity parameter in the mass and momentum conservation equations, and including an additional drag source term in the momentum equations. This paper presents and compares two different numerical discretizations for the two-dimensional shallow water equations with porosity, both of them are high-order schemes. The numerical schemes proposed are well-balanced, in the sense that they preserve naturally the exact hydrostatic solution without the need of high-order corrections in the source terms. At the same time they are able to deal accurately with regions of zero porosity, where the water cannot flow. Several numerical test cases are used in order to verify the properties of the discretization schemes proposed.

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An immersed boundary method for unstructured meshes in depth averaged shallow water models

Ouro

Cea

Ramírez

et al. 2015

Numerical Methods in Fluids

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Summary The representation of geometries as buildings, flood barriers or dikes in free surface flow models implies tedious and time‐consuming operations in order to define accurately the shape of these objects when using a body fitted numerical mesh. The immersed boundary method is an alternative way to define solid bodies inside the computational domain without the need of fitting the mesh boundaries to the shape of the object. In the direct forcing immersed boundary method, a solid body is represented by a grid of Lagrangian markers, which define its shape and which are independent from the fluid Eulerian mesh. This paper presents a new implementation of the immersed boundary method in an unstructured finite volume solver for the 2D shallow water equations. Moving least‐squares is used to transmit information between the grid of Lagrangian markers and the fluid Eulerian mesh. The performance of the proposed implementation is analysed in three test cases involving different flow conditions: the flow around a spur dike, a dam break flow with an isolated obstacle and the flow around an array of obstacles. A very good agreement between the classic body fitted approach and the immersed boundary method was found. The differences between the results obtained with both methods are less relevant than the errors because of the intrinsic shallow water assumptions. Copyright © 2015 John Wiley & Sons, Ltd.

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Application of Several Depth-Averaged Turbulence Models to Simulate Flow in Vertical Slot Fishways

Cited by 67 publications

References 23 publications

Numerical and physical model study of a vertical slot fishway

Numerical and physical model study of a vertical slot fishway

Unstructured finite volume discretization of two‐dimensional depth‐averaged shallow water equations with porosity

An immersed boundary method for unstructured meshes in depth averaged shallow water models

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