Influence of upstream turbulence on the wake characteristics of a tidal stream turbine
Influence of upstream turbulence on the wake characteristics of a tidal stream turbine
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DOI：
10.1016/j.renene.2018.08.055
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发表时间：
2019-03
期刊：
影响因子：
8.7
通讯作者：
M. Ahmadi
中科院分区：
文献类型：
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作者：
M. Ahmadi
研究了实验室尺度水平轴潮流涡轮机上游湍流强度对下游流动特性的影响。采用混合大涡模拟/激励线模拟技术，对三个具有相同平均速度和不同湍流强度的试验工况进行了数值模拟。沿流向沿着比较了平均速度分量、平均湍流脉动、速度亏损和尾流扩展，以考察上游湍流效应。入流条件是使用湍流明渠流实验获得的平均速度和湍流剖面通过映射方法生成的。结果表明，上游湍流度对涡轮机下游的流动特性有很大的影响，上游湍流度通过影响叶尖涡的破裂过程进而影响尾迹的恢复。比较还表明，环境湍流度强烈影响的速度赤字，但它并没有显着影响流向速度和径向位置的尖端涡在流中。
The influence of the upstream turbulence intensity on the flow characteristics downstream of a laboratory-scale horizontal axis tidal stream turbine is investigated in this study. Three test cases with the same mean velocity and different turbulence intensities are simulated numerically using the hybrid large eddy simulation/actuator line modelling technique. The mean velocity components, mean turbulent fluctuations, velocity deficit and wake extension are compared along the streamwise direction to examine the upstream turbulence effects. The inflow conditions are generated by the mapping method using the mean velocity and turbulent profiles experimentally obtained for a turbulent open channel flow. Comparing results for the mean velocity and turbulent fluctuations shows that the upstream turbulence level strongly affects the flow characteristics downstream of the turbine by influencing the tip vortices breakdown process and in turn wake recovery. The comparison also reveals that the ambient turbulence level strongly influences the velocity deficit but it does not significantly affect the streamwise velocity and the radial location of tip vortices in the flow.