Development and testing of a numerical code for treatment of complex river channel topography in three-dimensional CFD models with structured grids

Hardy, Richard J.; Lane, Stuart N.; Lawless, Mark; Best, James L.; Elliott, L.; Ingham, D.B.

doi:10.1080/00221680509500145

Cited by 50 publications

(57 citation statements)

References 47 publications

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“…The vegetation assessment took into account height, form, flexibility of the stem, plant leaf mass, density and spacing of plants (Sandercock and Hooke, 2010). To calculate hydraulics of flow WINXSPRO (Hardy et al, 2005), a program developed by the United States Department of Agriculture, was selected because it allows a cross-section to be divided into a number of subsections on the basis of morphology or vegetation, in which hydraulics of each could be calculated (Sandercock Table 2 Characteristics of three long-term monitored reaches in Cárcavo Basin. and Hooke, 2010).…”

Section: Reach Scalementioning

confidence: 99%

Vegetation effects on sediment connectivity and processes in an ephemeral channel in SE Spain

Sandercock¹,

Hooke²

2011

Journal of Arid Environments

104

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Section: Reach Scalementioning

confidence: 99%

Vegetation effects on sediment connectivity and processes in an ephemeral channel in SE Spain

Sandercock¹,

Hooke²

2011

Journal of Arid Environments

104

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“…Recently, a regular structured grid method based on numerical porosity has been developed and successfully tested in a laboratory setting to obtain a better representation of the complex surface topography of gravel-bed rivers in high-resolution 3D models (Lane et al 2004, Hardy et al 2005. This method is a modified version of a concept described by Olsen and Stokseth (1995) in which a digital elevation model (DEM) is used to assign a porosity value of zero to fully blocked cells, of one to fully unblocked cells, and between 0 and 1, based on the percentage of the cell that is blocked.…”

Section: Introductionmentioning

confidence: 99%

Assessing different methods of generating a three-dimensional numerical model mesh for a complex stream bed topography

Biron

Haltigin

Hardy

et al. 2007

International Journal of Computational Fluid Dynamics

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Three-dimensional numerical models of flow over complex bed geometry are becoming widely used in river and coastal engineering. Boundary-fitted coordinate grids are typically used to deal with this problem in natural channels. Recently, a regular structured grid method based on numerical porosity has been developed for high-resolution gravel-bed models. A simpler alternative approach is to use a Cartesian mesh with an interpolated 3D solid object representing the river bed. The objective of this study is to assess the impact of these three methods of mesh generation on the simulated flow field above complex bed topography around stream deflectors in a laboratory setting. Results show marked differences between the three types of simulations when running mesh sensitivity analysis. Because the bed porosity approach uses the digital elevation model (DEM) information in each cell to represent bed topography, it requires a finer mesh resolution in order to reach an accurate solution. Although there was good qualitative agreement between the simulated flow fields and Acoustic Doppler Velocity measurements, the quantitative comparison showed relatively poor agreement for all mesh design types. However, the three mesh types were in good agreement when compared to each other for velocity and pressure variables (average correlation coefficient, r, of 0.95), with the 3D object bed and bed porosity showing the best agreement (r ¼ 0.97). Simulated turbulence variables (KE and EP), however, showed more scatter (r ¼ 0.85) and slopes markedly different from unity.

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“…Much like long-term discharge records, such data sets would be a resource for all, useful for applications ranging from environmental assessment and change to modeling and theory development. Some of the immediate professional applications of these maps would include providing river data for advanced hydraulic models (Hardy et al, 2005), mapping of stream habitat units for stocking and for determining endangered organism status (Hedger et al, 2006), improving river visualizations , and monitoring erosion and deposition . Any of the applications discussed earlier in this article could potentially be mapped and monitored at basin extents to build catchment extent 'river observatories'.…”

Section: The Futurementioning

confidence: 99%

Optical remote mapping of rivers at sub‐meter resolutions and watershed extents

Marcus

Fonstad

2007

Earth Surf Processes Landf

243

196

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At watershed extents, our understanding of river form, process and function is largely based on locally intensive mapping of river reaches, or on spatially extensive but low density data scattered throughout a watershed (e.g. cross sections). The net effect has been to characterize streams as discontinuous systems. Recent advances in optical remote sensing of rivers indicate that it should now be possible to generate accurate and continuous maps of in‐stream habitats, depths, algae, wood, stream power and other features at sub‐meter resolutions across entire watersheds so long as the water is clear and the aerial view is unobstructed. Such maps would transform river science and management by providing improved data, better models and explanation, and enhanced applications. Obstacles to achieving this vision include variations in optics associated with shadows, water clarity, variable substrates and target–sun angle geometry. Logistical obstacles are primarily due to the reliance of existing ground validation procedures on time‐of‐flight field measurements, which are impossible to accomplish at watershed extents, particularly in large and difficult to access river basins. Philosophical issues must also be addressed that relate to the expectations around accuracy assessment, the need for and utility of physically based models to evaluate remote sensing results and the ethics of revealing information about river resources at fine spatial resolutions. Despite these obstacles and issues, catchment extent remote river mapping is now feasible, as is demonstrated by a proof‐of‐concept example for the Nueces River, Texas, and examples of how different image types (radar, lidar, thermal) could be merged with optical imagery. The greatest obstacle to development and implementation of more remote sensing, catchment scale ‘river observatories’ is the absence of broadly based funding initiatives to support collaborative research by multiple investigators in different river settings. Copyright © 2007 John Wiley & Sons, Ltd.

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Development and testing of a numerical code for treatment of complex river channel topography in three-dimensional CFD models with structured grids

Cited by 50 publications

References 47 publications

Vegetation effects on sediment connectivity and processes in an ephemeral channel in SE Spain

Vegetation effects on sediment connectivity and processes in an ephemeral channel in SE Spain

Assessing different methods of generating a three-dimensional numerical model mesh for a complex stream bed topography

Optical remote mapping of rivers at sub‐meter resolutions and watershed extents

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