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005			20260817172048.0
008			160698 th eng
035			_a.b11509879
099		9	_aAIT Thesis no. WA-92-8
100	0		_aGao Jiacai
245	1	0	_aCalculation of energy dissipation due to an abrupt bed drop in an open channel
260			_aBangkok : _bAsian Institute of Technology, _c1992
300			_a118 leaves
490	1		_aThesis ; _vno. WA-92-8
500			_aA thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology
502			_aThesis (M.Eng.) - Asian Institute of Technology, 1992
520			_aFlow energy dissipation due to an abrupt bed drop was previously studied extensively on a macroscopic scale, either by a one-dimensional (1-D) analysis or by experimental measurement. The macroscopic aspect of the flow phenomena and energy dissipation is well understood while the microscopic aspect has not been revealed clearly. A two-dimensional (2-D) hydrodynamic model in the vertical plane with the standard k - e turbulence model closure (VEST model) is used to compute the temporal mean flow parameters and turbulence characteristics of the flow through an abrupt bed drop in a microscopic scale. The numerical results are compared with the available experimental measurements. It is found that the model can predict the velocities accurately and can predict the turbulence characteristics reasonably well. The spatial distribution of the flow energy dissipation is computed along the longitudinal distance and a good agreement between the computed results and the previous experimental data is obtained. The effects of the inlet Froude number, the relative step height and the downstream end water level on the energy dissipation are examined. The computed energy dissipation is compared with those obtained by the classical 1-D analysis. The deviations of 1-D results from the 2-D model results are quantitatively evaluated. Sensitivity analysis are performed to investigate the effects of the k - e model constants, the upstream boundary conditions of the inlet velocity and the k and e turbulence characteristics, and the effects of the water surface boundary condition on the computed flow conditions and on the flow energy dissipation.
650	1	0	_aHydrodynamics _xMathematical models
700	0		_aTawatchai Tingsanchali, _eChairperson
700	0		_aSuphat Vongvisessomjai, _eExamination Committee
700	1		_aTanaka, Hitoshi, _eExamination Committee
700	1		_aTran Thuc, _eExamination Committee
710	2		_aGovernment of Denmark, _eScholarship Donor
810	2		_aAsian Institute of Technology. _tThesis ; _vno. WA-92-8
856			_3Full-Text _uhttp://203.159.5.9/ait-thesis/detail.php?q=B17255
907			_a.b11509879 _bmnait _cs
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