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Optimization and analysis of winglet configuration for solar aircraft

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Chinese Journal of Aeronautics 2020年第12期33卷 3238-3252页

作者： Liang ZHANG Dongli MA muqing yang Shaoqi WANG School of Aeronautic Science and Engineering Beihang UniversityBeijing 100083China Xi'an Modern Control Technology Research Institute Xi'an 710065China

Installing winglets can notably improve the aerodynamic performance of solar *** paper proposes a multi-constraints optimization method of winglets for solar aircraft,aiming to enhance the corresponding uninterrupted cruising *** optimization objective function is formed and is separately studied in aerodynamic and structural *** analysis shows that the winglet design parameters are restricted by four special constraints(geometry,aerodynamics,energy and stability)of solar *** optimization process is constructed on the basis of a multi-island genetic algorithm,and carried out for a 15 m wingspan solar *** the designed winglet is not as good as the traditional winglet in terms of drag and structural weight,the designed winglet provides a better 24 h cruising *** sensitivity between the objective function and the design parameters is investigated,and the winglet effects vary with respect to the wing aspect ratio(AR=10,15,19.6).The effect of the constraints is analysed quantitatively,and some basic laws are ***,the feasible design region and the possible optimal design parameters of winglets for different wing configurations are *** calculation results show that when the aspect ratio exceeds a certain value,the winglets will not benefit the aircraft.

关键词： Energy balance Lateral-directional stability Multi-constrained optimization Shading effect Solar aircraft Winglets

Dynamic simulation of aerial towed decoy system based on tension recurrence algorithm

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Chinese Journal of Aeronautics 2016年第6期29卷 1484-1495页

作者： Ma Dongli Wang Shaoqi yang muqing Dong Yongpan School of Aeronautic Science and Engineering Beihang University

Dynamic model of aerial towed decoy system is established and simulations are performed to research the dynamic characteristics of the system. Firstly, Kinetic equations based on spinor are built, where the cable is discretized into a number of rigid segments while the decoy is modeled as a rigid body hinged on the cable. Then tension recurrence algorithm is developed to improve computational efficiency, which makes it possible to predict the dynamic response of aerial towed decoy system rapidly and accurately. Subsequently, the efficiency and validity of this algorithm are verified by comparison with Kane’s function and further validated by wind tunnel *** results indicate that the distance between the towing point and the decoy’s center of gravity is suggested to be 5%–20% of the length of decoy body to ensure the stability of *** up-risen maneuver process, the value of angular velocity is recommended to be less than0.10 rad/s to protect the cable from the aircraft exhaust jet. During the turning movement of aircraft, the cable’s extent of stretching outwards is proportional to the aircraft’s angular ***, the decoy, aircraft and missile form a triangle, which promotes the decoy’s performance.

关键词： Numerical simulation Spinor Tension recurrence algorithm Towed cable Towed decoy

Optimization and analysis of composite sandwich box beam for solar drones

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Chinese Journal of Aeronautics 2021年第10期34卷 148-165页

作者： Liang ZHANG Dongli MA muqing yang Xinglu XIA Yuan YAO School of Aeronautic Science and Engineering Beihang UniversityBeijing 100083China

Solar drones have garnered considerably research attention in recent years due to their continuous cruising capability,and the feasibility of design schemes is sensitive to the weight of *** box beam composed of carbon fiber and polymethacrylimide(PMI)foam is conducive to realize the lightweight of *** this study,a two-stage optimization design methodology for sandwich box beam is *** methodology is primarily based on a low-order analytical method for evaluating stress/deflection and the linear buckling analysis method combined with experimental correction factor for predicting the buckling ***,a case study was conducted using an 18-m wingspan solar drone,where the results of mechanical test verified the optimization *** validating the use of sandwich box beam in solar drones of other scales,additional analysis was conducted based on three aspects:(A)effects of stiffness and stability constraints on the design of sandwich box beam;(B)crucial role of the weight of foam inter layer and application scope of sandwich box beam;(C)best method to improve the buckling eigenvalue of sandwich box ***,the methodology and general rules presented in this paper can support the design of light wing beam for solar drones.

关键词： Buckling analysis Low-order analytical method Multi-stage optimization Sandwich box beam Solar drones

Flight strategy optimization for high-altitude long-endurance solar-powered aircraft based on Gauss pseudo-spectral method

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Chinese Journal of Aeronautics 2019年第10期32卷 2286-2298页

作者： Shaoqi WANG Dongli MA muqing yang Liang ZHANG Guanxiong LI School of Aeronautic Science and Engineering Beihang University

Solar-powered aircraft have attracted great attention owing to their potential for longendurance flight and wide application *** to the particularity of energy system,flight strategy optimization is a significant way to enhance the flight performance for solar-powered *** this study,a flight strategy optimization model for high-altitude long-endurance solar-powered aircraft was *** model consists of three-dimensional kinematic model,aerodynamic model,energy collection model,energy store model and energy loss *** solve the nonlinear optimal control problem with process constraints and terminal constraints,Gauss pseudo-spectral method was employed to discretize the state equations and constraint *** a typical mission flying from given initial point to given final point within a time interval was *** indicate that proper changes of the attitude angle contribute to increasing the energy gained by photovoltaic *** of gravitational potential energy can partly take the role of battery *** these two measures,the optimized flight strategy can improve the final state of charge compared with current constant-altitude constant-velocity *** optimized strategy brings more profits on condition of lower sunlight intensity and shorter daytime.

关键词： Battery pack Flight strategy optimization Gauss pseudo-spectral method Photovoltaic cell Solar-powered aircraft

Numerical simulation of gurney flaps lift-enhancement on a low reynolds number airfoil

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Science China(Technological Sciences) 2017年第10期60卷 1548-1559页

作者： HE Xi WANG JinJun yang muqing MA DongLi YAN Chao LIU PeiQing Key Laboratory of Fluid Mechanics (Beihang University) Ministry of Education Belting 100191 China Institute of Aircraft Design Heihang University Beijing 100191 China

Two-dimensional steady Reynolds-averaged Navier-Stokes （RANS） equations with transition shear stress transport （SST） model were solved to investigate the effects of Gumey flaps on the aerodynamic performance of a low Reynolds number airfoil. This airfoil was designed for flight vehicles operating at 20 km altitude with freestream velocity of 25 rn/s. The chord length （C） of this airfoil is 5 m and the corresponding Reynolds number is 7.76× 10^5. Gurney flaps with the heights ranging from 0.25%C to 3%C were investigated. It has been shown that Gurney flaps can enhance not only the prestall lift but also lift-to-drag ratio in a certain range of angles of attack. Specially, at cruise angle of attack （3°）, Gurney flap with the height of 0.5%C can increase lift-to-drag ratio and lift coefficient by 1.6% and 12.8%, respectively. Furthermore, the mechanisms of Gumey flaps to improve the aerodynamic performance were illustrated by analyzing the surface pressure distribution, streamlines and trailing-edge flow structure for this low Reynolds number airfoil. Specially, distinguished from some other numerical researches, the flow details such as the laminar separation bubble and transition phenomena for low Reynolds number airfoil with Gumey flaps were investigated and it was found that Gurney flaps can delay the transition onset position at small angles of attack （≤2°）. However, with the increase of angles of attack, Gurney flaps will promote the boundary layer transition.

关键词： gurney flaps lift-enhancement low reynolds number numerical simulation

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网格资源的动态分配和管理技术研究

华中科技大学学报（自然科学版） 2007年第3期35卷 28-30页

作者：朱勇杨木清杨薇薇中南民族大学网络技术中心湖北武汉430074 华中科技大学计算机科学与技术学院湖北武汉430074

为了提高资源共享和协同工作效率,在现有网格资源管理体系结构基础上,对支持资源管理动态化的特性进行了改进,并提出了无间隔动态解决资源故障的算法.该算法将资源库中可运行的任务尽可能多地映射到相应的本地资源管理者,使资源能够进... 详细信息

为了提高资源共享和协同工作效率,在现有网格资源管理体系结构基础上,对支持资源管理动态化的特性进行了改进,并提出了无间隔动态解决资源故障的算法.该算法将资源库中可运行的任务尽可能多地映射到相应的本地资源管理者,使资源能够进行动态分配,从而使网格中面临的大量具有动态特性的资源管理问题变得容易,实现了对网格资源更加灵活高效的使用.

关键词：网格资源动态管理可扩展资源描述语言本地资源管理

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翼型近波浪水面气动特性研究

北京航空航天大学学报 2021年第12期47卷 2521-2532页

作者：胡浩德马东立杨穆清郭阳北京航空航天大学航空科学与工程学院北京100083

采用求解Navier-Stokes方程的数值方法研究了翼型NACA 4412近距离经过波浪水面时的气动特性。对数值方法的准确性进行了验证。计算了翼型经过波浪水面和固壁波浪地面2种边界条件下的气动力系数,并进行了对比。研究结果表明:翼型在经过... 详细信息

采用求解Navier-Stokes方程的数值方法研究了翼型NACA 4412近距离经过波浪水面时的气动特性。对数值方法的准确性进行了验证。计算了翼型经过波浪水面和固壁波浪地面2种边界条件下的气动力系数,并进行了对比。研究结果表明:翼型在经过波浪水面时气动力系数会发生周期性的变化,与固壁波浪的情况相比,气动力的变化曲线存在显著差异,波动幅度更大。通过对流场结构的分析,发现了翼型和波浪水面之间的作用机理。波浪水面的质点存在竖直方向上的运动,在小地面间隙时,水面质点向上运动会挤压翼型和水面之间的空气,从而造成翼型气动力大幅波动。同时解释了来流速度越大,气动力系数波动幅度减小的原因。

关键词：波浪地效气动力波幅流动机理挤压效应

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基于分段插值的水上无人机离水特性求解方法

航空学报 2017年第12期38卷 71-80页

作者：李陟马东立杨穆清郭阳胡浩德北京航空航天大学航空科学与工程学院北京100083

水上无人机成为无人机研究的新热点,其船体构型对离水特性影响巨大,构型参数设计合理可以减小滑跑距离和需用功率,反之会造成离水困难,甚至可能出现增加发动机功率水上飞机也无法离水的情况。这是由于其特殊的起降环境使得水上无人机起... 详细信息

水上无人机成为无人机研究的新热点,其船体构型对离水特性影响巨大,构型参数设计合理可以减小滑跑距离和需用功率,反之会造成离水困难,甚至可能出现增加发动机功率水上飞机也无法离水的情况。这是由于其特殊的起降环境使得水上无人机起飞过程受力情况较常规飞行器更加复杂,常规飞行器起飞性能计算方法对于水上无人机不再适用,所以对水上飞机起飞离水特性的求解十分重要。CFD的发展使得利用数值计算方法代替常规的试验手段成为了可能,但直接利用CFD软件仿真求解水上无人机/飞机的离水过程难度大,耗时长,可行性低。可根据CFD计算中库朗数条件对气动力和水动力求解要求的不同,采用解耦方法分别求解不同条件下水上无人机完整构型的气动力和船体构型的水动力;同时水上无人机在起飞滑跑过程中,垂向受力小、加速度小,可将垂向受力看做近平衡状态,这成为分段插值求解方法的基础。将离水起飞过程离散化,利用分段插值方法求解得到其起飞离水特性,计算结果可以很好体现水上无人机水面滑跑的特性,与试验结果吻合良好。

关键词：水上无人机离水特性分段插值方法近平衡假设解耦计算

Numerical simulation of Gurney flap on SFYT15thick airfoil

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Theoretical & Applied Mechanics Letters 2016年第6期6卷 286-292页

作者： Xi He Jinjun Wang muqing yang Dongli Ma Chao Yan Peiqing Liu Fluid Mechanics Key Laboratory of Education Ministry Beijing University of Aeronautics and Astronautics Institute of Aircraft Design Beijing University of Aeronautics and Astronautics

A two-dimensional steady Reynolds-averaged Navier-Stokes （RANS） equation was solved to investigate the effects of a Gurney flap on SFYT15 thick airfoil aerodynamic performance. This airfoil was designed for flight vehicle operating at 20 km altitude with freestream velocity of 25 m/s, The chord length （C） is 5 m and the Reynolds number based on chord length is Re = 7.76 × 10^5. Gurney flaps with the heights ranging from 0.25%C to 3%C were investigated. The shear stress transport （SST） k-ω turbulence model was used to simulate the flow structure around the airfoil. It is showed that Gurney flap can enhance not only the prestall lift but also lift-to-drag ratio in a certain range of angles of attack. Specially, at cruise angle of attack （ω = 3°）, Gurney flap with 0.5%C height can increase lift-to-drag ratio by 2.7%, and lift coefficient by 12.9%, respectively. Furthermore, the surface pressure distribution, streamlines and trailing-edge flow structure around the airfoil are illustrated, which are helpful to understand the mechanisms of Gurney flap on airfoil aerodynamic performance. Moreover, it is found that the increase of airfoil drag with Gurney flap can be attributed to the increase of pressure drag between the windward and the leeward sides of Gurney flat itself.

关键词： Lift enhancement Airfoil Gurney flap Numerical simulation