The tip leakage flow passed over the tip clearance makes the flow very complicated near the tip gap, and the interaction of the tip leakage vortex and endwall vortex enhances the instability of the flow. Accurately capturing detailed flow structures and investigating the relationship between the flow structures and loss are beneficial for understanding the flow physics and providing guidance on reducing the loss. Due to the conventional Reynolds Averaged Navier-Stokes (RANS) methods is limited to predict the complex turbulence structures of the tip clearance flow, high fidelity simulation approaches are needed. In this work, the hybrid RANS/Large Eddy Simulation (LES) is adopted to simulate the tip leakage flow in linear cascade and demonstrates its ability to capture the small-scale flow structures. With the POD method, the time-averaged flow field and the dominating modes are obtained. Based on the analysis of the POD modes, it is found that the induced vortex generated by the interaction between the leakage vortex and the endwall vortex has strong turbulence characteristics. Based on the entropy generation rates, viscous loss mechanism is further analyzed. It is found that the shear strain rates dominate the viscous dissipation losses, and the fluctuation dissipation has a strong local enhancement effect.

通过叶尖间隙的叶尖泄漏流使叶尖间隙附近的流动非常复杂，叶尖泄漏涡和端壁涡的相互作用增强了流动的不稳定性。准确捕捉详细的流动结构，研究流动结构与损耗的关系，有利于理解流动物理，为减少损耗提供指导。由于传统的雷诺平均纳维-斯托克斯 (RANS) 方法仅限于预测叶尖间隙流的复杂湍流结构，因此需要高保真度模拟方法。在这项工作中，混合RANS/大涡模拟（LES）被用来模拟线性叶栅中的尖端泄漏流，并展示了它捕捉小尺度流动结构的能力。使用 POD 方法，得到时均流场和主导模式。基于POD模态分析发现，泄漏涡与端壁涡相互作用产生的诱导涡具有较强的湍流特性。基于熵产生率，进一步分析粘性损失机制。发现剪切应变率在粘性耗散损失中占主导地位，波动耗散具有很强的局部增强效应。