Thesis
Numerical simulation of a submerged circular turbulent jet impinging on eroded boundaries
Washington State University
Master of Science (MS), Washington State University
2016
Handle:
https://hdl.handle.net/2376/102264
Abstract
Soil erosion is a natural process which may cause riverbank instability, loss of soil productivity, pollution of watercourses, and damage to infrastructure. The interaction among physical, chemical and biological properties are responsible for the complex process of cohesive soil erosion. Due to the site specific nature of soil erosion, field measurements are preferred to determine soil erodibility when estimating river bank erosion. The jet erosion test (JET) is a widely used in-situ test. The JET is a cost-effective tool to measure erodibility of cohesive soils. In this test, a submerged circular turbulent jet impinges on the soil surface and generates a scour hole. The erosion beneath the soil surface is assumed to be generated by the maximum shear stress produced by the jet. There are various empirical equations developed to calculate this shear stress. The erodibility of cohesive soil can be obtained from the analysis of JET results. In the analysis procedure the shape of the scour hole is not incorporated. In this study computational fluid dynamics (CFD) is applied to study the shear stress distribution of a circular turbulent jet impinging on various eroded boundaries. The results for the velocity, pressure and maximum shear stress obtained from the numerical simulations are compared with the case of a flat boundary (i.e., no erosion) as well as existing equations. The agreement with the flat boundary case was found to depend on the geometry of the scour region. The results demonstrate that the presence of scour hole region has impact on the near wall hydrodynamics and shear stress distribution. The incorporation of scour hole in the analysis of jet test results can be useful to better predict of erodibility of cohesive soil using the JET.
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Details
- Title
- Numerical simulation of a submerged circular turbulent jet impinging on eroded boundaries
- Creators
- Zannatul Ferdous Haque
- Contributors
- John Petrie (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Civil and Environmental Engineering, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525089201842
- Language
- English
- Resource Type
- Thesis