高超声速壁面黏性力快速计算方法

A rapid method for hypersonic skin viscous force calculation

当前高超声速飞行器壁面黏性力的预测方法主要有精确的Novier-Stokes方程CFD方法(计算流体力学)和快速工程计算方法。前者计算精度高,但效率很低;后者效率极高,但精度难以满足工程应用要求。如何将两种方法有效结合,发展具有一定精度且效率也较高的壁面黏性力计算方法,一直是计算空气动力学研究的重要方向之一。为此,本文基于无黏Euler方程CFD方法获得的壁面流场参数,发展了一种更加精确的高超声速飞行器壁面黏性力快速工程计算方法。该方法以经典参考温度法为基础,以壁面当地流场参数替代自由来流参数,更加充分地考虑了高超声速复杂流动的特性,从理论上提高了壁面黏性力的预测精度。为验证该方法的准确性,以典型高超声速高升阻比飞行器外形为研究对象,分别采用精确Navier-Stokes方程CFD方法和本文发展的快速工程计算方法,预测了高空高马赫数飞行环境下飞行器壁面的黏性力;通过对比分析表明,本文所建立的快速计算方法预测偏差为10~20%,能够满足工程初步设计的要求。

Accurate computational fluid dynamic(CFD)methods with Novier-Stokesequations and rapid engineering methods are currently two major approaches to obtain skin viscous force for hypersonic aircraft.The former is relatively accurate with poor efficiency,and the later is efficient with poor accuracy.How to combine the two methods and develop a new way with enough efficiency and accuracy is always an important aspect for computational aerodynamics.Therefor,a rapid engineering method to predict skin viscous force of hypersonic aircraft more accurately was developed with near-wall flow characteristics derived from invicid Euler equations.The method was based on the classical reference tem perature method and constructed with local flow parameters instead of free flow param eters,so that could count the hypersonic flow characteristics more adequately and achieve a more accurate prediction of skin viscous forces in theory.In order to examine the accuracy of the rapid method,forces of a typical hypersonic aircraft with high Lift-to-Drag ratio at hypersonic velocity and high altitude was calculated by a Navier-Stokes equations CFD method and the presented rapid method.The comparison analysis finally showed a relative deviation of丄0?20%from the rapid method,which could gave a good satisfaction for engineering applications.