高Ma数民用飞机声爆特性的非线性预测技术研究

Recently, with the demand of the development of high Mach number civil airline, sonic boom prediction technique has become the highlight. The current prediction approaches are all based on linear or quasi-linear theory, and can not satisfy the accuracy requirement. For example, the intensity of the pressure perturbation caused by the shock increases when the cruising altitude increases due to the decreasing of the environmental pressure, and so for the Mach number increases. These factors result in the decrease of the prediction accuracy. This program devotes to further develop the hybrid prediction method for sonic boom strength on the ground, which consists of two subitems: the high fidelity capturing of the off-body pressure distributions of the near field flow using CFD, and the far field pressure perturbation propagation using geometrical acoustic approach. The present work contains four aspects: modifying the existing geometrical acoustic approach for far field pressure signal propagation by considering nonlinear effects both in calculation of the intensity and distortion of the pressure perturbation; introducing the stratified atmosphere and the atmosphere turbulence effects to the propagation model; improving and demonstrating the high fidelity CFD capturing technique for the near field off-body pressure distributions; exploring the typical parameter and its effect law on the characters of the sonic boom. The numerical simulation and wind tunnel test are both combined to construct the highly efficient and highly reliable prediction method for high Mach number aircraft. This program is the fundamental research of the sonic boom prediction method for high Mach number civil transport, which might be a perfect technical reserve for the future low boom design of the high Mach number civil airline.

近年来，随着高Ma数民用飞机的发展需求，声爆特性预测技术的研究成为热点问题。当前广泛采用的声爆预测方法大都以线性化或者拟线性化方法为基础，当飞机巡航高度增加或飞行Ma数提升，压力扰动也呈增加趋势，这些因素将导致线性化近似误差增大。本项目拟进一步改进基于近场脱体压力精细捕捉和远场声爆传播解耦计算的混合型预测方法。重点研究四个方面的内容：通过同时在压力波远场传播过程的幅值计算和形状变化计算中同时考虑非线性影响，改进现有几何声学声爆传播方法存在的不足；在远场传播模型中引入大气物性参数随高度变化以及大气湍流的影响；提升并试验验证近场脱体压力的精确捕捉技术；探索影响声爆特性的典型因素。将采用数值模拟和风洞验证试验相结合的方法，建立高Ma数飞机声爆强度预测的高效、高可靠性方法。本项目为高Ma数飞机声爆特性预测相关技术的应用基础研究，将为未来我国高Ma数民用飞机低声爆气动布局设计方面提供良好的技术储备。

近年来，随着高Ma数民用飞机的发展需求，声爆特性预测技术的研究成为热点问题。当前广泛采用的声爆预测方法大都以线性化或者拟线性化方法为基础，当飞机巡航高度增加或飞行Ma数提升，压力扰动也呈增加趋势，这些因素将导致线性化近似误差增大。本项目进一步改进基于近场脱体压力精细捕捉和远场声爆传播解耦计算的混合型预测方法。重点研究四个方面的内容：通过同时在压力波远场传播过程的幅值计算和形状变化计算中同时考虑非线性影响，改进现有几何声学声爆传播方法存在的不足；在远场传播模型中引入大气物性参数随高度变化以及大气湍流的影响；提升并试验验证近场脱体压力的精确捕捉技术；探索影响声爆特性的典型因素。采用数值模拟和风洞验证试验相结合的方法，建立高Ma数飞机声爆强度预测的高效、高可靠性方法。