飞行器气动参数的集员辨识

在噪声未知但有界的情况下，本文研究了飞行器气动参数的集员辨识问题。提出了先对非线性系统参数可行集的中心进行估计，再估计参数可行集大小的集员辨识两步法。这样就为解决飞行器气动参数的辨识问题提供了一种新的可行方法，再入体实测数据的处理表明这种方法十分有效。     

Computational study of wing deformation and sting interference effects with the CAE-AVM test case

A modern transonic computational fluid dynamics test case is described in this paper, which is the Aerodynamic Validation Model (AVM) from the Chinese Aeronautical Establishment (CAE). The CAE-AVM is a representation of a modern transonic business jet aircraft with a design Mach number of 0.85. Numerical simulations for the AVM are conducted for two geometries: one baseline geometry, and one geometry that includes the applied model support system of the wind tunnel as well as the deformed wing shape that occurred during wind tunnel testing. The combined influence of wing deformation and model support interference on local and integral aerodynamic features is presented. Comparisons between CFD and experimental results are made; reasons of discrepancy between results from considered cases are analyzed.     

Aerodynamic database development of the ESA intermediate experimental vehicle

This work deals with the aerodynamic database development of the Intermediate Experiment Vehicle.     

火箭协同优化中的气动代理模型研究

随着运载火箭研发模式转变，快速迭代和协同优化设计成为主要发展方向，这就要求作为小回路论证中重要一环的气动特性计算能够实现在线输出数据，亟需研究一种快速计算气动特性的代理模型，代替耗时的CFD计算和风洞试验参与到总体优化设计中。综合比较多种快速计算途径，选择高斯基Kriging插值和BP神经网络两种方法构建代理模型。使用脚本控制的Cart3D软件生成数值试验样本，样本点精度与Fluent软件计算误差小于14%。通过样本点训练、内参优化和加点策略，最终获得相对误差小于10%的代理模型，能够实现给定外形参数在线秒级输出气动数据，极大地推动了气动计算在总体论证中的作用。     

天问一号着陆器大底分离触发条件设计方法

针对天问一号着陆器防热大底分离触发条件确定问题,利用数学仿真的方法分析气动特性、防热大底相对着陆器姿态运动等因素对分离安全性的影响,给出可安全分离的触发条件.不同分离触发马赫数的仿真结果表明,较大分离马赫数的碰撞风险较高,但防热大底长期运动趋势由弹道系数决定,相比着陆器下降更快.根据伞降过程着陆器姿态运动及伞绳力特点,...     

Effect of surface blowing on aerodynamic characteristics of tubercled straight wing

Recent research proves that wings with leading-edge tubercles have the ability to perform efficiently in post-stall region over the conventional straight wing. Moreover, the conventional straight wing outperforms the tubercled wing at a pre-stall region which is quintessential. Even though tubercled wing offers great performance enhancement, because of the complexity of the flow, the trough region of the tubercled wing is more prone to flow separation. Henceforth, the present paper aims at surface blowing – an active flow control technique over the tubercled wing to enhance the aerodynamic efficiency by positively influencing its lift characteristics without causing any additional drag penalty. Flow parameters like blowing velocity ratios and the location of blowing were chosen to find the optimised configuration keeping the amplitude and frequency of the leading-edge tubercles constant as 0.12 c and 0.25 c respectively. Numerical investigations were carried out over the baseline tubercled wing and tubercled wing with surface blowing at various blowing jet velocity ratios 0.5, 1 and 2 over four different chordwise locations ranging from 0.3 c to 0.8 c.The results confirm that blowing at various x/c with different blowing velocity ratios performs better than the conventional tubercled wing. Comparatively, blowing velocity ratio 2 at 0.3 c shows peak performance of about 28% enhancement in the lift characteristics relative to the baseline model. Particularly, in the pre-stall region, 25–50% increase in aerodynamic efficiency is evident over the tubercled wing with surface blowing compared with the baseline case. Additionally,attempts were made to delineate the physical significance of the flow separation mechanism due to blowing by visualizing the streamline pattern.     

Aerodynamic multi-objective integrated optimization based on principal component analysis

Based on improved multi-objective particle swarm optimization (MOPSO) algorithm with principal component analysis (PCA) methodology,an efficient high-dimension multiobjective optimization method is proposed,which,as the purpose of this paper,aims to improve the convergence of Pareto front in multi-objective optimization design.The mathematical efficiency,the physical reasonableness and the reliability in dealing with redundant objectives of PCA are verified by typical DTLZ5 test function and multi-objective correlation analysis of supercritical airfoil,and the proposed method is integrated into aircraft multi-disciplinary design (AMDEsign) platform,which contains aerodynamics,stealth and structure weight analysis and optimization module.Then the proposed method is used for the multi-point integrated aerodynamic optimization of a wide-body passenger aircraft,in which the redundant objectives identified by PCA are transformed to optimization constraints,and several design methods are compared.The design results illustrate that the strategy used in this paper is sufficient and multi-point design requirements of the passenger aircraft are reached.The visualization level of non-dominant Pareto set is improved by effectively reducing the dimension without losing the primary feature of the problem.     

超跨声速无导叶对转涡轮整流型动叶设计

为了探讨对转涡轮气动设计规律，采用常用于导叶的可控涡法设计对转涡轮上游整流动叶，并配合可控子午成型设计，用以控制对转涡轮内径向压力分布，并与传统涡轮进行了深入对比分析。该方法设计的5．25kg／s小流量模型对转涡轮效率为94．2％。三维数值模拟表明：对转涡轮取消导叶后，在设计自由度减小，参数受到制约条件下，整流动叶采用可控涡设计是调控对转涡轮流场积极有效措施之一。     

基于气/固耦合非定常流动的叶栅颤振分析

采用二维N-S方程／结构振动方程组耦合数值方法，分析计算了二维非定常气动力强迫振动条件下振动能量及气动力对叶栅所做的功，分别根据振动能量和气动力做功分析了叶栅的颤振特性。NACA0012和PROF叶栅在不同折合频率下气动参数随时间的变化表明，折合频率是影响叶栅颤振的重要因素。气固耦合方法得到的NA-CA0012叶栅颤振折合频率比非耦合的结果高，而对PROF叶栅则相反。这表明叶栅结构动力参数对其发生颤振时的折合频率影响很大且很复杂，要准确预测颤振应该考虑叶栅结构动力与气动力的耦合因素。     

螺旋桨性能计算的升力线与升力面方法

基于改进升力线方法，编制了螺桨升力线方法计算程序，并以此为基础，在桨尖外一层虚网格和虚控制点，得升力线理论中导出的附着涡和自由涡的积分公式，发展了一种螺旋动性能计算的升力面方法，该方法具有简洁、方便，实用等特点，用本文发展的升力线和升力面方法对多个螺旋桨算例进行了计算，计算结果与实验结果符合良好。