旋翼VPM/CFD耦合模型的建立及其在小前进比气动分析中的应用

为了提高旋翼计算流体力学（CFD）流场计算效率及克服其在尾迹捕捉上的不足，将旋翼黏性涡粒子方法（VPM）与CFD分析相结合，建立了一个新的旋翼VPM/CFD耦合气动分析模型。在该模型中，采用VPM分析以实现对旋翼尾迹中黏性涡的高效捕捉而不引入数值耗散，而采用CFD分析用于精确地模拟旋翼桨叶近体区域内复杂的流动现象，同时也为VPM分析提供一个较高精度的涡源模型。至于两者信息交换，则使用集中涡源法将CFD信息传递至VPM分析，而VPM计算得到的尾迹信息则通过边界修正施加至CFD域的远场边界上，从而可以鲁棒地实现CFD域与VPM域的耦合计算。在此基础上，对“Helishape 7A旋翼”小前进比前飞桨-涡干扰（BVI）状态进行了较为深入的气动分析，计算结果表明：与全CFD计算比较，建立的VPM/CFD耦合分析模型可以有效地避免旋翼尾迹区桨尖涡的数值耗散，从而更加可靠地捕捉桨-涡干扰状态下的桨叶非定常气动载荷脉动，同时对于本文算例，计算效率可以提高30%以上。

Development of a Coupled VPM/CFD Model and Its Application to Aerodynamic Analysis of Rotors at Low Advance Ratios

In order to improve the computational efficiency and wake capturing resolution in rotor computational fluid dynamics (CFD) analysis, a new hybrid aerodynamic analysis model is developed through coupling viscous vortex particle method (VPM) with CFD. In this model, VPM simulates the rotor wake variation without any numerical dissipation, and CFD predicts the complicated flow phenomenon in the vicinity of a blade accurately, and provides precise vorticity sources for VPM. The integrated vorticity source method is adopted to transfer the CFD information into VPM, while the boundary correction method is employed to impose the VPM wake information on the CFD outer boundary; thus an efficient and robust coupling scheme is established. Based on the aforementioned method, the blade-vortex interaction (BVI) of "Helishape 7A rotor" at low advance ratio is investigated, and the results indicate that the VPM/CFD coupling method developed in this paper avoids numerical dissipation more effectively as compared with the full CFD method, while airload fluctuations in the BVI condition can be captured more reliably. Furthermore, the computational efficiency enhancement can be over 30% in the present analysis scenario.