基于系统优势函数和IAHP的预警机作战效能评估

针对预警机作战效能评估中作战效能的系统性和评估数据的不确定性问题,在建立预警机作战效能评估指标体系的基础上,建立基于系统优势函数和IAHP的预警机作战效能评估模型,并利用该模型对担负电子对抗任务的预警机作战效能进行分析。实例表明,加强分系统之间的协同合作是提高预警机作战效能的有效方法。     

E-2C预警机在航母编队中的作战使用

介绍了E-2C预警机在航母编队中的使命、作战指挥流程、作战部署和防空作战使用，给出了预警区域、预警时间、漏警率等预警机基本效能参数。     

预警机系统及其在防空作战中的运用

预警机在现代战争中起着兵力倍增器的作用,是提高军队整体作战效能的有效途径,能有效打击敌方的隐蔽目标及一些特殊目标。文中主要对空中预警机的组成、作用、关键技术作了详细的分析,并对预警机在防空作战中的运用进行了探讨。     

装备假目标防空作战仿真及效能分析

介绍了假目标的概念、功能及在战争中的运用;综述了假目标技术及作战运用研究现状;从 4个方面建立了假目标在防空中的作战效能评估模型;应用蒙特卡洛法对假目标防空作战过程进行仿真,并对假目标的防空作战效能进行了计算分析。     

预警机跑道形巡航探测效能研究

对预警机跑道形巡航时的探测效能问题进行了研究。基于SEA的基本原理,阐述了预警机跑道形巡航探测效能问题,给出了跑道形巡航想定和预警机在此作战环境和作战样式下的MOP集合,重点研究了MOP的系统映射模型,建立了在相对坐标系下分析预警机探测概率和平均覆盖时间的模型,指出了对MOP的使命映射研究方法,采用SEA方法对预警机跑道形巡航探测效能进行了分析。算例说明了模型的正确性。     

地空导弹武器系统射击效能评估模型研究

地空导弹武器系统射击效能评估是防空作战中必须进行的环节,受多种因素的综合制约,对其进行科学的定量计算分析,将会对防空作战产生重大的影响。文中应用模糊数学中的模糊综合评判方法,建立了射击效能评估的数学模型,并引入"5分制"的量化方法对评估结果进行了量化处理。最后应用该模型对一实例进行了分析,得到了满意的结果。此模型可为防空作站指挥人员提供重要的决策依据。     

基于任务协同的有人机/无人机 对海攻击作战效能评估研究

通过分析攻击敌海上舰船目标过程中有人机/无人机编队的作战使用方式及影响其作战效能的主要因素,建立了有人机/无人机编队协同攻击海上目标的作战效能评估指标体系,运用ADC法构建了有人机/无人机混合编队攻击敌舰船目标作战效能评估模型,通过算例证明了该方法适应于有人机/无人机编队的作战效能评估,为有人机/无人机协同作战决策提供了有效的参考依据。     

基于主成分分析和支持向量机的作战飞机效能评估

作战飞机效能的评估是防空作战中的重要问题,简述了效能评估的各种方法,建立参数效能模型时,首先要挑选特征参数,用主成分分析方法选择武器的特征参数。利用支持向量机建立了作战飞机的参数效能模型,通过实例与神经网络法的结果进行了比较,结果表明支持向量机比较精确和简单。     

单舰防空反导综合作战效能评估

单舰防空反导综合作战效能反映了水面舰艇对空防御能力,它不仅是舰艇战斗力生成的基础,也是舰艇持续作战的根本保证.在反导作战效能评估中,专家咨询法、层次分析法等都存在一定主观因素,文中提出的基于概率学的分类综合评价法,不仅可以客观地评价单舰防空综合反导作战效能,还能应用于对作战方法优劣的评价,对改进战法,提高水面舰艇战斗力...     

潜艇防空导弹武器系统综合作战效能评估研究

以某潜艇防空导弹武器系统的作战过程为对象,建立了该武器系统综合作战效能的指标体系,采用层次分析法(AHP法)与专家组决策法(Delphi法)相结合的方法确定各指标的权重,并且对各指标进行量化后规范化处理,给出分级的潜艇防空导弹武器系统综合作战效能综合评估模型,并举例进行定量分析和计算。     

翼梢装置对机翼颤振特性影响研究

机翼加装翼梢装置在气动上可以起到减小飞机的诱导阻力、提高升阻比、耗散强翼梢涡等作用,但是它也使飞机的结构特性发生了变化,尤其是颤振特性。采用MSCPatran,MSCFlds建立基本翼及几种带翼梢装置机翼的动力学有限元模型和非定常空气动力网格,应用MSCNastran求解序列SOL103对其进行固有模态分析,利用求解序列SOL145进行颤振分析,通过对比分析得到翼梢装置对机翼的振动和颤振特性影响,为飞机翼梢装置设计提供依据。     

翼梢装置对机翼气动、结构特性影响研究

主要研究了不同翼梢装置对飞机气动、结构特性的影响。对几种带翼梢装置机翼的气动特性N-S计算结果进行对比分析,揭示了不同翼梢装置的减阻机理及对飞机气动性能的影响。采用MSC Patren,MSC Flds建立基本翼及几种带翼梢装置机翼的动力学有限元模型和非定常空气动力网格,应用MSC Nastran求解序列SOL103对其进行固有模态分析,利用求解序列SOL 145进行颤振分析,通过对比分析得到翼梢装置对机翼的振动和颤振特性影响。     

翼梢装置对某机翼气动弹性行为影响研究

以大客某方案机翼为基本翼,通过数值模拟的方法研究了翼梢装置对机翼气动弹性特性影响,包括静气动弹性及颤振特性。其中通过CFD/CSD弱耦合求解的方法研究其静气动弹性响应,气动力计算采用面元法,结构响应计算采用结构有限元法,通过插值实现翼面气动力与有限元节点力之间的传递,以及有限元模型与气动网格之间的变形传递。对基本翼及带翼梢装置机翼静力学有限元模型局部修改得到动力学模型,应用MSC NASTRAN进行颤振特性分析。研究发现翼梢装置使得机翼的气动弹性特性不同程度均有降低,而不同翼梢装置对其影响又有所不同,可见,翼梢装置的设计在追求气动特性改善的同时必须关注其带来的结构特性的损失。     

带翼梢小翼亚音速机翼的升阻特性计算

 本文采用的有限基本解方法,以等转角法划分展向网格和确定展向控制点位置。对带翼梢小翼亚音速矩形翼进行了升力计尊,并用联合流场法计算了诱导阻力。从各种方案的翼梢小翼计算中,找到了一些影响机翼升阻特性的规律和较佳方案,并对其机理作了分析。     

舰载机折叠翼气动特性分析

折叠翼技术是舰载机与航母相匹配的关键,研究折叠翼的气动特性对舰载机飞行动态及安全性具有重要意义。基于离散化的思想对折叠翼进行建模,并利用计算流体力学CAE软件Fluent对其进行数值计算,从升力系数和阻力系数变化及压力分布分析舰载机折叠翼的气动特性。结果表明:当折叠角为75°时,外翼的升力系数及侧向力系数将达到最大,阻力系数最小;一旦折叠机构失效,外翼的折叠将导致机翼整体升力系数及阻力系数大幅度下降,气动特性变差;与折叠机构失效前相比,折叠后的机翼失速迎角变小,且在失速后升力系数有缓慢上升趋势。     

变体翼梢小翼的减阻机理数值模拟

总结了对翼梢小翼减阻效果影响最大的几何参数,在此基础上采用数值模拟方法研究了这些几何参数的最佳变化范围,为变体翼梢小翼设计提供理论依据.并从气动性能、气动载荷分布和翼尖涡的角度探讨了变体翼梢小翼相对传统翼梢小翼的优缺点.结果表明:在飞机的起飞阶段,变体翼梢小翼的减阻效率比传统翼梢小翼高2.2%,同时将翼尖涡强度降低了15%,有利于提高飞机的燃油效率和机场空域安全;但也会增大机翼的翼根弯矩,因此必须权衡变体翼梢小翼带来的气动收益与结构强度不利因素.     

Supersonic biplane—A review

One of the fundamental problems preventing commercial transport aircraft from supersonic flight is the generation of strong sonic booms. Sonic booms are the ground-level manifestation of shock waves created by airplanes flying at supersonic speeds. The strength of the shock waves generated by an aircraft flying at supersonic speed is a direct function of both the aircraft’s weight and its occupying volume; it has been very difficult to sufficiently reduce the shock waves generated by the heavier and larger conventional supersonic transport (SST) configuration to meet acceptable at-ground sonic-boom levels. It is our dream to develop a quiet SST aircraft that can carry more than 100 passengers while meeting acceptable at-ground sonic-boom levels. We have started a supersonic-biplane project at Tohoku University since 2004. We meet the challenge of quiet SST flight by extending the classic two-dimensional (2-D) Busemann biplane concept to a 3-D supersonic-biplane wing that effectively reduces the shock waves generated by the aircraft. A lifted airfoil at supersonic speeds, in general, generates shock waves (therefore, wave drag) through two fundamentally different mechanisms. One is due to the airfoil’s lift, and the other is due to its thickness. Multi-airfoil configurations can reduce wave drag by redistributing the system’s total lift among the individual airfoil elements, knowing that wave drag of an airfoil element is proportional to the square of its lift. Likewise, the wave drag due to airfoil thickness can also be nearly eliminated using the Busemann biplane concept, which promotes favorable wave interactions between two neighboring airfoil elements. One of the main objectives of our supersonic-biplane study is, with the help of modern computational fluid dynamics (CFD) tools, to find biplane configurations that simultaneously exhibit both traits. We first re-analyzed using CFD tools, the classic Busemann biplane configurations to understand its basic wave-cancellation concept. We then designed a 2-D supersonic biplane that exhibits both wave-reduction and cancellation effects simultaneously, utilizing an inverse-design method. The designed supersonic biplane not only showed the desired aerodynamic characteristics at its design condition but also outperformed a zero-thickness flat-plate airfoil. (Zero-thickness flat-plate airfoils are known as the most efficient monoplane airfoil at supersonic speeds.) Also discussed in this paper is how to design 2-D biplanes, not only at their design Mach numbers but also at off-design conditions. Supersonic biplanes have unacceptable characteristics at their off-design conditions such as flow choking and its related hysteresis problems. Flow choking causes rapid increase of wave drag and it continues to be kept up to the Mach numbers greater the cruise (design) Mach numbers due to its hysteresis. Some wing devices such as slats and flaps, which could be used at take-off and landing conditions as high-lift devices, were utilized to overcome these off-design problems. Then supersonic-biplane airfoils were extended to 3-D wings. Because that rectangular-shaped 3-D biplane wings showed undesirable aerodynamic characteristics at their wingtips, a tapered-wing planform was chosen for the study. A 3-D biplane wing having a taper ratio and aspect ratio of 0.25 and 5.12, respectively, was designed utilizing the inverse-design method. Aerodynamic characteristics of the designed biplane wing were further improved by using winglets at its wingtips. Flow choking and its hysteresis problems, however, occurred at their off-design conditions. It was shown that these off-design problems could also be resolved by utilizing slats and flaps. Finally, a study on the aerodynamic characteristics of wing-body configurations was conducted using the tapered biplane wing. In this study a body was chosen in order to generate strong shock waves at its nose region. Preliminary parametric studies on the interference effects between the body and the tapered biplane wing were performed by choosing several different wing locations on the body. From this study, it can be concluded that the aerodynamic characteristics of the tapered biplane wing are minimally affected by the disturbances generated from the body, and that the biplane wing shows promise for quiet commercial supersonic transport.     

翼梢小翼的气动特性计算和实验验证

 本文用有限基本解法,对带翼梢小翼后掠翼的亚音速升阻特性进行了计算,并计算了其俯仰力矩和翼根弯矩。通过各种形式翼梢小翼的计算,分析了翼梢小翼气动特性的一般规律。计算结果与实验数据的比较表明,本方法可满足翼梢小翼初步设计和选型的需要。     

地面效应下前/后掠翼气动特性研究

针对飞行器在地效区飞行时复杂的流场特性,通过求解定常可压N-S方程,改变机翼后掠角和地效区飞行高度,研究不同前/后掠角机翼在地效区内的气动特性。结果表明:在地效区内,随着后掠角的增大,机翼的升力系数和阻力系数呈现先增后减的变化规律,后掠角在0°附近时升力系数达到最大值,阻力系数在10°附近达到最大值;俯仰力矩系数随着后掠角增加而减小;展向流动在后掠角为0°时最小,展向流动随着后掠角增大或减小剧烈变化;机翼下洗角随着后掠角增大而减小,随着离地高度的减小而减小。研究结果可为地效飞行器的概念方案设计和优化提供理论依据。     

环翼机低速气动特性风洞实验研究

环翼机具有前、后翼,前翼后掠,后翼前掠,机翼在翼尖处连接,形成一个环状结构。为了解环翼的气动特性及环翼的几何参数对环翼机气动特性的影响,本文在低速风洞中对3种不同几何参数环翼飞机进行了纵向及横向测力实验,其中包括前、后翼几何参数改变对气动特性的影响。实验结果表明,与常规飞机相比,环翼机具有如下优点：诱导阻力小,失速特性好,操稳性能易于满足。实验得到的有价值结果,对环翼布局飞机的气动计算和合理设计具有重要意义。