发表机构
University of Exeter; University of Brighton（埃克塞特大学; 布莱顿大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过直接模拟蒙特卡洛方法，考察了角半径和克努森数对顶盖驱动空腔稀薄气体流动的影响，发现尖角近似能捕捉全局速度结构，但会忽略局部流动和热力学响应。
AI 中文摘要
在采用理想化几何表示稀薄空腔流动时，有限角曲率通常被忽略。本研究考察了下游角倒圆对顶盖驱动空腔流动的影响，覆盖克努森数Kn从0.5到5的范围。针对归一化角半径Rc = 0、0.10和0.20进行了直接模拟蒙特卡洛计算。模型通过已发表的基准数据和局部网格敏感性测试进行了评估。分析了速度场、中心线剖面、面积平均速度、平动温度、数密度和温度各向异性。在所有情况下均存在一个单一的主涡旋。角倒圆改变了下游回流流动的局部转向，但对更广泛的环流影响甚微。倒圆与尖角中心线速度剖面之间的均方根差异保持在0.007以下。在所有倒圆构型中，面积平均归一化速度均有所增加，最大变化约为2.5%。热力学响应显示出对稀薄程度的更强依赖性。在Kn = 0.5和1时，角倒圆降低了平均温度不均匀性，但在Kn = 2和5时则增加了该不均匀性。平均密度偏差的变化保持在约1.3%以内，而平均平动温度各向异性的变化范围约为-3%至2.4%。结果表明，在所研究的条件下，尖角近似能够捕捉全局速度结构，但可能忽略与有限角曲率相关的局部流动变化和较小的热力学响应。
英文摘要
Finite corner curvature is commonly omitted when rarefied cavity flows are represented using idealised geometries. This study examines how downstream corner rounding affects lid-driven cavity flow over 0.5 $\le$ Kn $\le$ 5. Direct simulation Monte Carlo calculations were performed for normalised corner radii of Rc = 0, 0.10 and 0.20. The model was assessed through published benchmark data and a local grid-sensitivity test. Velocity fields, centreline profiles, area-averaged speed, translational temperature, number density and temperature anisotropy were analysed. A single primary vortex persisted across all cases. Corner rounding modified the local turning of the downstream return flow but caused little change in the wider circulation. The root-mean-square differences between the rounded and sharp-cornered centreline velocity profiles remained below 0.007. The area-averaged normalised speed increased in all rounded configurations, with a maximum change of approximately 2.5%. The thermodynamic response showed a stronger dependence on rarefaction. Corner rounding reduced the mean temperature non-uniformity at Kn = 0.5 and 1, but increased it at Kn = 2 and 5. Changes in the mean density deviation remained within approximately 1.3%, while the mean translational-temperature anisotropy varied from about -3% to 2.4%. The results show that the sharp-corner approximation captures the global velocity structure under the conditions studied, but can omit local flow changes and small thermodynamic responses associated with finite corner curvature.
