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基于非结构动态网格重构技术,采用SA模型以及VOF方法,分别对NACA0012二维翼型自由空间、近地效应以及近水面效应的非定常运动流场进行了数值计算分析,并根据建立的基于小幅度强迫振动的组合动导数辨识方法计算了各个攻角下动导数。计算结果分析表明动导数计算方法准确可靠;中小攻角下,地面与水面以管道效应影响流场,均损失了动态阻尼,柔性的水面损失更多,动导数绝对值更小;大攻角时,两者表现为阻塞效应,柔性水面下的动态阻尼增大,动导数绝对值也变大;相比地面效应,柔性的水面影响范围更广。
Based on the unstructured dynamic grid reconstruction technique and the SA model and the VOF method, the unsteady flow fields of NACA0012 two-dimensional airfoil free space, near-surface effect and near-surface effect are numerically calculated and analyzed. According to the established The dynamic derivative at each angle of attack is calculated based on the combined dynamic derivative identification method with small amplitude forced vibration. The calculation results show that the method of calculating the dynamic derivatives is accurate and reliable. Under medium and small attack angles, both the ground and the surface of the water affect the flow field by pipeline effect, losing dynamic damping, more flexible surface loss and smaller absolute value of dynamic derivatives. , Both of them show obstruction effect, the dynamic damping under flexible surface increases, and the absolute value of dynamic derivative becomes bigger. Compared with the ground effect, the flexible water surface has a wider range of influence.