用全位势方程计算机翼的亚声速,跨声速和超声速绕流

对大后掠小展弦比细长机翼,本文对机翼纵轴垂直的每一横流截面生成O型网格,形成对机翼流场的H-O型网格,用守恒型全位势方程、差分和隐式近似因式分解迭代算法计算绕机翼的可压缩位流。自由流可从亚声速直到低超声速的全部跨声速范围。本算法要求机翼前缘有大后掠角,后缘可稍许后掠或前掠。本文算例表明,所研制的计算程序已可提供工程实用。

Computation of Subsonic, Transonic and Supersonic Flows past the Wing Using Full-Potential Equation

To compute the compressible flow past slender wings with high sweep, this paper uses conservative full-potential equation and 'H-O' grid. The 'H-O' grid used is created by generating a series ot 2-D 'O' meshes around the cross-flow sections perpendicular to the wing axis. The full-potential equation is solved by finite-difference method and the iteration scheme of implicit approximate factorization, proposed by Hoist. Such a grid is suitable especially to handle slender configurations. Because the grid used has one family of the grid lines which are in direction close to the stream, it is easy to introduce the time-like dissipation for iteration convergence in supersonic region even when the free stream Mach number is greater than one. Thus the computer code developed with the present method can apply not only to subsonic and transonic free streams but also to lower supersonic one. They cover almost the whole range of the transonic flow. The compulation results arc given for two wings. The one is a cropped delta wing with leading edge sweep of 65% the free stream Mach numbers are from 0.6 to 1.4. The other is a swept wing of NASA TN D-712. M1 the compulations give good results.