旋转执行器线系统的高阶CFD建模
High-Order CFD Modeling of Rotating Actuator Line Systems
AI总结：
本研究开发耦合FR/CPR格式与ALM的高阶CFD框架，无需显式叶片几何即可模拟全旋转涡轮机，经两叶片VAWT测试，可可靠捕捉强非定常下的叶片载荷、流场及尾流特征。
AI中文摘要：
高阶计算流体动力学（CFD）方法结合基于执行器的叶片表示，为旋转能源系统的模拟提供了一种极具吸引力的途径。本研究开发了一种高阶计算框架，将通量重构/通过重构的校正程序（FR/CPR）格式与旋转执行器线模型（ALM）耦合。叶片旋转和非定常气动力通过施加在固定笛卡尔网格上的随时间变化的源项来实现，该方法无需显式叶片几何即可模拟全旋转涡轮机。气动力载荷采用准稳态翼型数据计算，并通过高斯平滑分布到流场中，以维持高阶格式的数值稳定性。该框架通过运行在低叶尖速比（TSR）下的两叶片垂直轴风力涡轮机（VAWT）进行测试，分析了相位平均的叶片运动和总载荷以研究其随方位角的变化，此外还检查了瞬时和平均流场以描述尾流结构和非定常涡脱。通过与实验测量值及文献中报道的叶片解析大涡模拟（LES）结果进行比较，使用归一化平均尾流速度剖面进行验证。结果表明，所提出的高阶虚拟体框架能够在保持几何简洁性的同时，可靠地捕捉强非定常条件下的主要叶片载荷趋势、流场结构和尾流特征。
英文摘要：
High-order computational fluid dynamics (CFD) methods combined with actuator-based blade representations provide an attractive approach for simulating rotating energy systems. In this work, we develop a high-order computational framework that couples the flux reconstruction/correction procedure via reconstruction (FR/CPR) formulation with a rotating actuator line model (ALM). Blade rotation and unsteady aerodynamic forces are implemented through time-dependent source terms applied on a fixed cartesian grid. This approach allows simulations of a fully rotating turbine without using explicit blade geometry. Aerodynamic loads are computed using quasi-steady airfoil data and distributed into the flow field with Gaussian smoothing to maintain numerical stability in the high-order scheme. The framework is tested using a two-bladed vertical-axis wind turbine (VAWT) operating at a low tip speed ratio (TSR). The phase-averaged blade motion and overall load are analyzed to study variations with azimuthal angle. In addition, instantaneous and mean flow fields are examined to describe wake structure and unsteady vortex shedding. Normalized mean wake velocity profiles are used for validation through comparison with experimental measurements and blade-resolved large-eddy simulations (LES) reported in the literature. The results show that the proposed high-order virtual-body framework can reliably capture major blade-loading trends, flow organization, and wake features under strongly unsteady conditions, while maintaining geometric simplicity.
