论文标题
执行器线方法的非二词基于涡旋的涂抹校正
Non-iterative vortex-based smearing correction for the actuator line method
论文作者
论文摘要
执行器线方法(ALM)广泛用于风力涡轮机和转子模拟中。但是,其原始的未校正配方高估了叶片尖端附近的力,并且在翻译翅膀时不会繁殖良好的力。最近提出的基于涡旋的ALM涂抹校正是基于模拟的物理和数学特性的校正,可提供更准确和更一般的ALM。到目前为止,要纠正刀片上的力,涂抹校正取决于每个时间步骤的迭代过程,通常比直接方法较慢,稳定和确定性较低。在这项工作中,提出了一个非著作过程和验证。首先,我们提出了一个非线性起重线的公式,该公式与ALM进行了涂抹校正,表明它们的结果实际上与翻译机翼相同。然后,通过线性化提升线方法,校正的迭代过程被小型线性系统的直接解代替。在机翼和转子模拟中,在迭代和非著作校正的结果中均未观察到显着差异。本工作的其他贡献包括使用更准确的近似值用于由涂抹的涡流段引起的速度以及实现自由涡流唤醒模型来定义涡流表,从而有助于该方法的准确性和通用性。这里存在的结果可能会激发其他社区(例如,在固定翼申请中)对ALM的采用。
The actuator line method (ALM) is extensively used in wind turbine and rotor simulations. However, its original uncorrected formulation overestimates the forces near the tip of the blades and does not reproduce well forces on translating wings. The recently proposed vortex-based smearing correction for the ALM is a correction based on physical and mathematical properties of the simulation that allows for a more accurate and general ALM. So far, to correct the forces on the blades, the smearing correction depended on an iterative process at every time step, which is usually slower, less stable and less deterministic than direct methods. In this work, a non-iterative process is proposed and validated. First, we propose a formulation of the non-linear lifting line that is equivalent to the ALM with smearing correction, showing that their results are practically identical for a translating wing. Then, by linearizing the lifting line method, the iterative process of the correction is substituted by the direct solution of a small linear system. No significant difference is observed in the results of the iterative and non-iterative corrections, both in wing and rotor simulations. Additional contributions of the present work include the use of a more accurate approximation for the velocity induced by a smeared vortex segment and the implementation of a free-vortex wake model to define the vortex sheet, that contribute to the accuracy and generality of the method. The results present here may motivate the adoption of the ALM by other communities, for example, in fixed-wing applications.