高超声速平板边界层数值模拟及试验研究

Numerical Simulation and Experimental Study on Hypersonic Plate Boundary Layer

高超声速边界层是一个基础的科学问题。为了研究高超声速平板边界层的流场特性,结合数值模拟、理论求解和试验验证三种手段进行综合分析。数值模拟对二维Navier-Stokes(N-S)方程采用五阶精度的WENO格式离散对流项、六阶中心格式离散黏性项,时间推进项采用三阶Runge-Kutta法。理论分析利用四阶Runge-Kutta结合打靶法求解得到可压缩平板边界层层流自相似解。试验验证利用中科院力学所JF-12复现风洞测试得到大尺度平板的壁面热流,大尺度的平板模型布置传感器达到了较高的空间分辨率,可捕捉到之前由于模型尺寸限制而被淹没的物理现象。研究发现,数值模拟高超声速平板边界层时可以通过给定自相似解的入口条件,规避前缘激波带来的影响;大尺度平板边界层试验重复性好,测量得到的热流在层流阶段与自相似解以及数值模拟得到的结果符合较好,可为现有的气体模型以及热物性参数模型的完善提供一种新的思路。

The hypersonic boundary layer is a basic scientific problem.In order to study the characteristics of the flow field in the boundary layer of a hypersonic plate,three methods are combined:numerical simulation,theoretical analysis,and experimental verification for comprehensive analysis.The numerical simulation is based on the two-dimensional Navier-Stokes equation,using the fifth-order weighted essentially non-oscillatory(WENO)scheme and the six-order central difference discretization for the convective and viscous terms respectively,and the time term is integrated by the third-order Runge-Kutta method.Theoretical analysis uses the fourth-order Runge-Kutta combined with the shooting method to obtain the flat-plate laminar boundary layer self-similar solution.The JF-12 duplicated wind tunnel test of the Institute of Mechanics has obtained the wall heat flow of large-scale flat plates for analysis.The sensors arranged in the large-scale flat-plate model achieve a high spatial resolution and can capture the physical phenomena that were previously submerged due to the limitation of the model size.It is found that the numerical simulation of the boundary layer of a flat plate can avoid the influence of the leading-edge shock by giving the entrance conditions of the self-similar solution.The large-scale flat-plate boundary layer experiment has good reproducibility,and the measured heat flow in the laminar phase agrees well with the self-similar solution and the boundary layer obtained by numerical simulation,which can provide a new idea for the improvement of existing gas models and thermophysical parameter models.