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最近,张涵信等人在传统的Beam-Warming隐式、无迭代、空间推进技术的基础上,根据边界层方程的性质,设计了一种可用小步长推进求解抛物化NS(PNS)方程、而不会引起解的“漂移现象”发生的方法。这种方法对轴对称流动的计算是成功的。本文就是将这一思想推广应用于大攻角有周向分离的流场计算。求解的区域为具有薄亚声速层的有粘与无粘干扰的整个激波层内的流场。在对攻角α=0°和α=20°的球钝锥的计算中,关于壁面上的压力、热流率及流场的涡旋结构均得到了满意的结果。文中特别研究了钝锥大攻角绕流的流动分离图象。 为了增强块三对角矩阵的主对角优势,通常在差分方程的左端附加二阶增量项。本文以选取适当小的推进步长的方法来达到增强主对角优势的目的,不需再附加二阶增量项,从而提高了解的精度。
Recently, based on the traditional Beam-Warming implicit, non-iterative and space propulsion techniques, Zhang Hanxin et al. Designed a solvable NS (PNS) equation based on the nature of the boundary layer equations Ways that do not cause the “drift phenomenon” of solution to occur. This method of calculation of axisymmetric flow is successful. This article is to apply this idea to the flow field calculation with circumferential separation at high angle of attack. The solution area is the flow field within the entire shock wave layer with a thin sub-sonic layer with both sticky and non-stick interference. In the calculation of the spherical obtuse cone at angles of attack α = 0 ° and α = 20 °, satisfactory results have been obtained with respect to the pressure on the wall, the heat flux and the eddy structure of the flow field. In particular, the flow separation of the blunt cone at a large angle of attack is investigated. To enhance the main diagonal dominance of the block tridiagonal matrix, second-order incremental terms are usually appended to the left end of the difference equation. In this paper, we choose the appropriate small step-by-step method to achieve the purpose of enhancing the main diagonal advantage, without the need for additional second-order incremental terms, thereby enhancing the accuracy of understanding.