An open-source 2D Reynolds-averaged Navier–Stokes (RANS) simulation model was presented and applied for a laboratory-scaled cross-flow hydrokinetic turbine and a twin turbine system in counter-rotating configurations. The computational fluid dynamics (CFD) model was compared with previously published experimental results and then used to study the turbine power output and relevant flow fields at four blockage ratios. The dynamic stall effect and related leading edge vortex (LEV) structures were observed, discussed, and correlated with the power output. The results provided insights into the blockage effect from a different perspective: The physics behind the production and maintenance of lift on the turbine blade at different blockage ratios. The model was then applied to counter-rotating configurations of the turbines and similar analyses of the torque production and maintenance were conducted. Depending on the direction of movement of the other turbine, the blade of interest could either produce higher torque or create more energy loss. For both of the scenarios where a blade interacted with the channel wall or another blade, the key behind torque enhancement was forcing the flow through its suction side and manipulating the LEV.

中文翻译：

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对错流式流体动力涡轮机的动态失速效应及因流动阻塞引起的相关扭矩增强的数值研究

提出了一种开源 2D 雷诺平均纳维-斯托克斯 (RANS) 模拟模型，并将其应用于实验室规模的错流流体动力涡轮机和反向旋转配置的双涡轮机系统。将计算流体动力学 (CFD) 模型与先前公布的实验结果进行比较，然后用于研究涡轮机功率输出和四种堵塞比下的相关流场。动态失速效应和相关的前缘涡 (LEV) 结构被观察、讨论并与功率输出相关联。结果从不同的角度提供了对阻塞效应的见解：在不同阻塞率下涡轮叶片上产生和维持升力背后的物理原理。然后将该模型应用于涡轮机的反向旋转配置，并对扭矩产生和维护进行类似的分析。根据另一个涡轮机的运动方向，感兴趣的叶片可能会产生更高的扭矩或产生更多的能量损失。对于叶片与通道壁或另一个叶片相互作用的两种情况，扭矩增强背后的关键是迫使气流通过其吸力侧并操纵 LEV。