水体在有压扩散段内的流动特性研究
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摘要
有压泄水隧洞的出水口处一般都是渐扩段。由于水流在扩散前流速较大,而扩散后流速较小,水流流速在短时间内发生了较大变化,因此会产生多种复杂的水流现象——流动分离、回流或漩涡等。主要针对对称渐扩段内的水流流态情况,利用Fluent软件,采用大涡模拟法得到特定雷诺数情况下,扩散角大于或等于7°时,对称扩散段内会发生主流来回摆动现象;当扩散角为特定角度时,在一定的雷诺数范围内,扩散段内主流来回摆动的起始时间随雷诺数增大提前,主流摆动的振幅随雷诺数增大而增大。
The outlet of the tunnel with pressure drainage is generally a gradually expanding section. The water flow velocity will change greatly in a short time because of larger flow velocity before diffusion and smaller flow velocity after diffusion. Therefore, there will be many complex flow phenomena-flow separation,backflow or eddy. Mainly aiming at the water flow patterns within the symmetrically gradually expanding section, the large-eddy simulation is used to achieve the phenomenon of the mainstream oscillation from back to forth with the symmetrically gradually expanding section when the diffusion angle is greater than or equal to 7 degrees by the Fluent software under the condition of specific Reynolds number. When the diffusion angle is a specific angle, within a certain Reynolds number range, the starting time of the mainstream oscillation in the diffusion section is ahead of schedule with the increase of Reynolds number, and the amplitude of the mainstream oscillation increases with the increase of Reynolds number.
The outlet of the tunnel with pressure drainage is generally a gradually expanding section. The water flow velocity will change greatly in a short time because of larger flow velocity before diffusion and smaller flow velocity after diffusion. Therefore, there will be many complex flow phenomena-flow separation,backflow or eddy. Mainly aiming at the water flow patterns within the symmetrically gradually expanding section, the large-eddy simulation is used to achieve the phenomenon of the mainstream oscillation from back to forth with the symmetrically gradually expanding section when the diffusion angle is greater than or equal to 7 degrees by the Fluent software under the condition of specific Reynolds number. When the diffusion angle is a specific angle, within a certain Reynolds number range, the starting time of the mainstream oscillation in the diffusion section is ahead of schedule with the increase of Reynolds number, and the amplitude of the mainstream oscillation increases with the increase of Reynolds number.
引文
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[2]陈玲莉,谢壮宁.渐扩管内流动特性的理论分析与试验研究[J].风机技术,1994,6(2):25-29.
[3]孙智一,吴晓蓉.计算流体力学数值模拟方法的探讨及应用[J].水利科技与经济,2008,14(2):126-128.
[4]叶东辉.基于Open FOAM的船舶水动力学应用关键技术分析[D].武汉:华中科技大学,2013.
[5]朱士江,李占松.突扩流动主流偏转特性数值模拟研究[J].水科学进展,2009,20(2):249-254.
[6]高学平,宋慧芳,赵耀南.恒定有压扩散流中的局部非稳态流动试验研究[J].水动力学研究与进展A辑,2007(2):182-187.