| Numerical Experiment on Two-Dimensional Line Thermal |
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| 引用本文： | J.H.W.LEE,G.Q.CHEN(陈国谦). Numerical Experiment on Two-Dimensional Line Thermal[J]. 中国海洋工程, 2002, 16(4): 453-467 |
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| 作者姓名： | J.H.W.LEE G.Q.CHEN(陈国谦) |
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| 作者单位： | Department of Civil Engineering，University of Hong Kong，Hongkong，China，National Laboratory for Turbulence，Peking University，Beijing 100871，China |
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| 基金项目： | 国家重点基础研究发展计划(973计划) |
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| 摘 要： | The time evolution of a two-dimensional line thermal-a turbulent flow produced by an initial element with signifi-cant buoyancy released in a large water body, is numerically studied with the two-equation k - e model for turbulence closure. The numerical results show that the thermal is characterized by a vortex pair flow and a kidney shaped concentra-tion structure with double peak maxima; the computed flow details and scalar mixing characteristics can be described by self-similar relations beyond a dimensionless time around 10. There are two regions in the flow field of a line thermal: a mixing region where the concentration of tracer fluid is high and the flow is turbulent and rotational with a pair of vortex eyes, and an ambient region where the concentration is zero and the flow is potential and well-described by a model of doublet with strength very close to those given by early experimental and analytical studies. The added virtual mass coeffi-cient of the thermal motion is found to be approximat
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Numerical Experiment on Two-Dimensional Line Thermal |
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| J.H.W.LEE. Numerical Experiment on Two-Dimensional Line Thermal[J]. China Ocean Engineering, 2002, 16(4): 453-467 |
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| Authors: | J.H.W.LEE |
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| Affiliation: | Department of Civil Engineering, University of Hong Kong, Hongkong, China National Laboratory for Turbulence, Peking University, Being 100871 , China |
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| Abstract: | The time evolution of a two-dimensional line thermal-a turbulent flow produced by an initial element with signifi-cant buoyancy released in a large water body, is numerically studied with the two-equation k - e model for turbulence closure. The numerical results show that the thermal is characterized by a vortex pair flow and a kidney shaped concentra-tion structure with double peak maxima; the computed flow details and scalar mixing characteristics can be described by self-similar relations beyond a dimensionless time around 10. There are two regions in the flow field of a line thermal: a mixing region where the concentration of tracer fluid is high and the flow is turbulent and rotational with a pair of vortex eyes, and an ambient region where the concentration is zero and the flow is potential and well-described by a model of doublet with strength very close to those given by early experimental and analytical studies. The added virtual mass coeffi-cient of the thermal motion is found to be approximately 1. The aspect ratio for the kidney-shaped sectional thermal is found to be around l .45 for the self-similar phase. The predicted thermal spreading and mixing rate compares well with experimental data. |
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| Keywords: | thermals and puffs turbulence modeling plumes and jets environmental fluid mechanics vortex flow added virtual mass mixing and transport. |
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