用粘流－无粘流相互作用方法计算翼型的分离和失速

本文用势流－边界层相互作用方法计算低速翼型的分离和失速。势流用对称面元法。边界层用改进的滞后掺混法，考虑了高阶项影响，适用于计算分离。文中对粘流－无粘流耦合方法作了改进。改进的半反－局部联立耦合方法，考虑了相邻点之间的作用，收敛性较好。计算了ＮＡＣＡ４４１２翼型在不同迎角下的压力分布和气动力。计算结果与实验符合良好。算例表明，翼型高升力状态计算必须包括尾流的作用，也应当对势流计算压力与实际压力之间的差别进行修正。

Computation of Flow Separation and Stall on Low Speed Airfoils by Viscous-Inviscid Interaction

A method for the computation of flow separation andstall on low speed airfoils by viscous-inviscid interaction is presented.Potential flow calculation is performed by a symmetric panel method hav-ing the merits bf low leakage and good accuracy.The boundary layer flow iscomputed With a modified lagentrainment method which includes higher or-der terms and makes use of a family of velocity profiles applicable to bothattached ahd separated flows.The principle of viscous-inviscid matchingis discussed.The method used in the present work is named semi-inverse/lo-cal-simultaneous matching,taking account of the influences of neighbouringpoints and thus improving the accuracy and convergence of the iterations.pressure distributions and aerodynamic forces at various angles of attackfor a NACA4412 airfoil are computed, with emphasis on separated flowsand stall conditions.Agreement with experimental results is satisfactory.It is found that at high angles of attack the effect of the wake on theflows and on the resulting forces is quite remarkable and must be includedin the computation.The difference between the calculated inviscid sur-face pressure and that of real viscous flow also should be corrected athigh lift conditions.