World Environmental and Water Resources Congress 2020
3D CFD Simulation: Terrain-Conforming versus Terrain-Embedding Method
Publication: World Environmental and Water Resources Congress 2020: Hydraulics, Waterways, and Water Distribution Systems Analysis
ABSTRACT
Three-dimensional (3D) computational fluid dynamic (CFD) simulation is gaining popularity in recent years for stream flow modelling. It is necessary when local flow patterns are of interest and/or there exist in-stream structures. Representation of complex terrain, however, is a major obstacle in 3D CFD modelling. Traditionally, the terrain-conforming method is widely used in which terrains are accurately represented by a 3D mesh; i.e., the mesh conforms to the terrain geometry. This method is straightforward in implementation and accurate in resolving the near-terrain flows. A drawback is that such a mesh is difficult to generate when the terrains are complex. The mesh quality may become too poor to maintain solution stability and accuracy. An alternative is the terrain-embedding method with which terrains are embedded in a background mesh. The background mesh may be generated without the requirement of conforming to the terrain so that mesh generation is relatively simple and good mesh quality may be maintained. Special algorithm, however, is needed to take into account the effect of the embedded terrains on the nearby flow. In this study, both CFD methods are adopted to simulate a selected flow case. The objective is to understand the pros and cons of the two methods through a real laboratory case, not merely in theory. The study is to pave a way to simulate sediment transport and scour cases when stream bed is moving.
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Published In
World Environmental and Water Resources Congress 2020: Hydraulics, Waterways, and Water Distribution Systems Analysis
Pages: 1 - 11
Editors: Sajjad Ahmad, Ph.D., and Regan Murray, Ph.D.
ISBN (Online): 978-0-7844-8297-1
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© 2020 American Society of Civil Engineers.
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Published online: May 14, 2020
Published in print: May 14, 2020
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