Unsteady Reynolds-Averaged Navier–Stokes (URANS) and SST-based improved delayed detached eddy simulation (SST-IDDES) are used to compare the performance, flow field characteristics, and downstream turbine installation distance of a Marine Current Turbine (MCT). The flow domain is discretized with unstructured tetrahedral mesh using the Fluent 2020R1 meshing tool, sliding mesh method used for turbine rotation. The governing equation’s convergence conditions are set to 10^–5. Second-order backward Euler and central differencing schemes are utilized for temporal and spatial discretization. It is found that power and torque coefficients predicted by both models match well with the available experimental data. The URANS model predicts relatively lesser transient properties than the IDDES model due to its isotropic character. Because of its anisotropic nature, the SST-based IDDES model predicts higher turbulence intensity. For both models, the tip vortex diffused near wake (3D) region, whereas the hub vortex diffused at 18D in URANS and 16.5D in SST-IDDES, supporting the assessment of downstream turbine installation distance. The percentage difference of power coefficient for both models is 2%, and the thrust coefficient is 1% at the optimum TSR (= 3.8). It is demonstrated that the SST-IDDES model is regarded as a reliable model to analyze the wake characteristics of marine current turbines.

不稳定雷诺平均纳维-斯托克斯 (URANS) 和基于 SST 的改进延迟分离涡模拟 (SST-IDDES) 用于比较海流涡轮机 (MCT) 的性能、流场特性和下游涡轮机安装距离。使用 Fluent 2020R1 网格划分工具，使用非结构化四面体网格对流动域进行离散化，滑动网格方法用于涡轮机旋转。控制方程的收敛条件设置为 10 ^–5. 二阶后向欧拉和中心差分方案用于时间和空间离散化。发现两种模型预测的功率和​​扭矩系数与可用的实验数据匹配良好。由于其各向同性特性，URANS 模型预测的瞬态特性比 IDDES 模型相对较小。由于其各向异性的性质，基于 SST 的 IDDES 模型预测了更高的湍流强度。对于这两个模型，尖端涡在尾流 (3D) 区域附近扩散，而中心涡在 URANS 中扩散到 18D，在 SST-IDDES 中扩散到 16.5D，支持下游涡轮机安装距离的评估。两种型号的功率系数百分比差异为 2%，推力系数在最佳 TSR (= 3.8) 时为 1%。