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Design concepts of an aircraft wing： composite and morphing airfoil with auxetic structures

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Frontiers of Structural and Civil Engineering 2016年第4期10卷 394-408页

作者： P R BUDARAPU Sudhir Sastry Y B R NATARAJAN department of Aerospace Engineering Indian Institute of Science Bangalore 560 012 India department of aeronautical Engineering College of Engineering Defence University Ethiopia department of aeronautical Engineering Institute of Aeronautical Engineering Hyderabad India

This paper is categorized into two parts. （1） A frame work to design the aircraft wing structure and （2） analysis ofa morphing airfoil with auxetic structure. The developed design frame work in the first part is used to arrive at the sizes of the various components of an aircraft wing structure. The strength based design is adopted, where the design loads are extracted from the aerodynamic loads. The aerodynamic loads acting on a wing structure are converted to equivalent distributed loads, which are further converted point loads to arrive at the shear forces, bending and twisting moments along the wing span. Based on the estimated shear forces, bending and twisting moments, the strength based design is employed to estimate the sizes of various sections of a composite wing structure. A three dimensional numerical model of the composite wing structure has been developed and analyzed for the extreme load conditions. Glass fiber reinforced plastic material is used in the numerical analysis. The estimated natural frequencies are observed to be in the acceptable limits. Furthermore, the discussed design principles in the first part are extended to the design of a morphing airfoil with auxetic structure. The advantages of the morphing airfoil with auxetic structure are （i） larger displacement with limited straining of the components and （ii） unique deformation characteristics, which produce a theoretical in-plane Poisson＇s ratio of -1. Aluminum Alloy AL6061-T651 is considered in the design of all the structural elements. The compliance characteristics of the airfoil are investigated through a numerical model. The numerical results are observed to be in close agreement with the experimental results in the literature.

关键词： wing design aerodynamic loads morphing airfoil auxetic structures negative Poisson's ratio

Turbulence modelling of the aerodynamic interaction ofOGV wakes and diffuser flow

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航空动力学报 2011年第10期26卷 2302-2312页

作者： Page Gary McGuirk Jim department of aeronautical and Automotive Engineering Loughborough University

Different turbulence closures were used to predict the flow interaction between the wakes created by compressor outlet guide vanes(OGVs) and a downstream annular *** statistical turbulence models were tested based on the classical Reynolds-averaged Navier-Stokes(RANS) *** high-Re and low-Re(Launder-Sharma) versions of the k-ε model were applied to a selected test problem for OGV wake/diffuser *** test problem was specifically chosen because experimentally determined inlet conditions and both profile and performance data were available to validate predictions.A preliminary study was also reported of the more advanced large eddy simulation(LES) *** LES sub-grid-scale(SGS) model was the basic Smagorinsky eddy viscosity assumption,with a Van-Driest damping function for improved capture of near-wall viscous *** between the two RANS models showed little difference in terms of velocity contours at OGV trailing edge and diffuser *** terms of overall diffuser performance(static pressure recovery and total pressure loss coefficients),the high-Re model was shown to agree well with experimental *** preliminary LES study indicates the highly unsteady character of the OGV wake flow,but requires improved treatment of inlet conditions.

关键词： outlet guide vane(OGV) wakes diffuser flow interaction Reynolds-averaged Navier-Stokes(RANS) modelling large eddy simulation(LES) modelling

Optimized Design of Bio-Inspired Wind Turbine Blades

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Fluid Dynamics & Materials Processing 2024年第7期20卷 1647-1664页

作者： Yuanjun Dai Dong Wang Xiongfei Liu Weimin Wu School of Mechanical Engineering Shanghai DianJi UniversityShanghai201306China School of Information Engineering Yinchuan University of Science and TechnologyYinchuan750000China School of Mechanical and Power Engineering Chongqing University of Science and TechnologyChongqing401331China School of aeronautical Mechanical and Electrical Engineering Chongqing Aerospace PolytechnicChongqing400021China

To enhance the aerodynamic performance of wind turbine blades,this study proposes the adoption of a bionic airfoil inspired by the aerodynamic shape of an *** on the blade element theory,a non-uniform extraction method of blade elements is employed for the optimization design of the considered wind turbine ***,Computational Fluid Dynamics(CFD)is used to determine the aerodynamic performances of the eagle airfoil and a NACA2412 airfoil,thereby demonstrating the superior aerodynamic performance of the ***,a mathematical model for optimizing the design of wind turbine blades is introduced and a comparative analysis is conducted with respect to the aerodynamic performances of blades designed using a uniform extraction *** is found that the blades designed using non-uniform extraction exhibit better aerodynamic performance.

关键词： Airfoil wind turbines blade design CFD

A numerical optimization of high altitude testing facility for wind tunnel experiments

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Chinese Journal of Aeronautics 2015年第3期28卷 636-648页

作者： J.Bruce Ralphin Rose G.R.Jinu C.J.Brindha department of aeronautical Engineering Regional Centre of Anna University department of Mechanical Engineering University College of EngineeringNagercoil department of aeronautical Engineering The Raajas Engineering College

Abstract High altitude test facilities are required to test the high area ratio nozzles operating at the upper stages of rocket in the nozzle full flow conditions. It is typically achieved by creating the ambient pressure equal or less than the nozzle exit pressure. On average, air/GN2 is used as active gas for ejector system that is stored in the high pressure cylinders. The wind tunnel facilities are used for conducting aerodynamic simulation experiments at/under various flow velocities and operating conditions. However, constructing both of these facilities require more laboratory space and expensive instruments. Because of this demerit, a novel scheme is implemented for conducting wind tunnel experiments by using the existing infrastructure available in the high altitude testing （HAT） facility. This article presents the details about the methods implemented for suitably modifying the sub-scale HAT facility to conduct wind tunnel experiments. Hence, the design of nozzle for required area ratio A/A＊, realization of test section and the optimized configuration are focused in the present analysis. Specific insights into various rocket models including high thrust cryogenic engines and their holding mechanisms to conduct wind tunnel experiments in the HAT facility are analyzed. A detailed CFD analysis is done to propose this conversion without affecting the existing functional requirements of the HAT facility.

关键词： CFD Enclosed free-jet section Ground testing High altitude testing (HAT)facility Optimization

Highly maneuvering target tracking using multi-parameter fusion Singer model

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Journal of Systems Engineering and Electronics 2017年第5期28卷 841-850页

作者： Shuyi Jia Yun Zhang Guohong Wang Research Institute of Information Fusion Naval Aeronautical and Astronautical University department of Aircraft Engineering Naval Aeronautical and Astronautical University

An algorithm of highly maneuvering target tracking is proposed to solve the problem of large tracking error caused by strong maneuver. In this algorithm, a new estimator, named as multi-parameter fusion Singer (MF-Singer) model is derived based on the Singer model and the fuzzy reasoning method by using radial acceleration and velocity of the target, and applied to the problem of maneuvering target tracking in strong maneuvering environment and operating environment. The tracking performance of the MF-Singer model is evaluated and compared with other manuevering tracking models. It is shown that the MF-Singer model outperforms these algorithms in several examples.

关键词： maneuvering target multi-parameter fusion Singer (MF-Singer) fuzzy reasoning Singer model

A distributed cooperative guidance law for salvo attack of multiple anti-ship missiles

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Chinese Journal of Aeronautics 2015年第5期28卷 1438-1450页

作者： Zhang Youan Wang Xingliang Wu Huali department of Control Engineering Naval Aeronautical and Astronautical University

The consensus problem of impact time is addressed for multiple anti-ship missiles. A new distributed cooperative guidance law with the form of biased proportional navigation guidance （BPNG） is presented. The proposed guidance law employs the available measurements of relative impact time error as the feedback information to achieve the consensus of impact time among mis- siles and, by exploiting the special structure of the biased cooperative control term, it can handle the seeker＇s field-of-view （FOV） constraint. The proposed scheme ensures convergence to consensus of impact time under either fixed or switching sensing/communication network, and the topological requirements are less restrictive than those in the existing results. Numerical examples are provided to illustrate the effectiveness of the proposed guidance law.

关键词： Cooperative Distributed Field-of-view constraint Missile guidance Missile trajectory control

Distributed H_∞ control of multi-agent systems with directed networks

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Chinese Physics B 2015年第9期24卷 73-79页

作者：刘伟柳爱利周绍磊 department of Control Engineering Naval Aeronautical and Astronautical University

This paper studies the distributed H∞control problem of identical linear time invariant multi-agent systems subject to external disturbances. A directed graph containing a spanning tree is used to model the communication topology. Based on the relative states of the neighbor agents and a subset of absolute states of the agents, distributed static H∞controllers are proposed. The concept of an H∞performance region is extended to the directed graph situation. Then the results are used to solve the leader–follower H∞consensus problem. Sufficient conditions are proposed based on bounded real lemma and algebraic graph theory. The effectiveness of the theoretical results is illustrated via numerical simulations.

关键词： multi-agent systems H∞ control performance region leader–follower H∞ consensus

Guidance law with impact time and impact angle constraints

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Chinese Journal of Aeronautics 2013年第4期26卷 960-966页

作者： Zhang Youan Ma Guoxin Liu Aili department of Control Engineering Naval Aeronautical and Astronautical University

A novel closed-form guidance law with impact time and impact angle constraints is pro- posed for salvo attack of anti-ship missiles, which employs missile＇s normal acceleration （not jerk） as the control command directly. Firstly, the impact time control problem is formulated as tracking the designated time-to-go （the difference between the designated impact time and the current flight time） for the actual time-to-go of missile, and the impact angle control problem is formulated as tracking the designated heading angle for the actual heading angle of missile. Secondly, a biased proportional navigation guidance （BPNG） law with designated heading angle constraint is constructed, and the actual time-to-go estimation for this BPNG is derived analytically by solving the system differential equations. Thirdly, by adding a feedback control to this constructed BPNG to eliminate the time-to-go errorthe difference between the standard time-to-go and the actual time-to-go, a guidance law with adjustable coefficients to control the impact time and impact angle simultaneously is developed. Finally, simulation results demonstrate the performance and feasibility of the proposed approach.

关键词： Feedback control Guidance law Impact angle Impact time Missiles Proportional navigation guidance

Lifetime prediction based on Gamma processes from accelerated degradation data

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Chinese Journal of Aeronautics 2015年第1期28卷 172-179页

作者： Wang Haowei Xu Tingxue Mi Qiaoli Graduate Students’ Brigade Naval Aeronautical and Astronautical University department of Ordnance Science and Technology Naval Aeronautical and Astronautical University

Accelerated degradation test is a useful approach to predict the product lifetime at the normal use stress level, especially for highly reliable products. Two kinds of the lifetime prediction based on Gamma processes were studied. One was to predict the lifetime of the population from accelerated degradation data, and the other was to predict the lifetime of an individual by taking the accelerated degradation data as prior information. For an extensive application, the Gamma process with a time transformation and random effects was considered. A novel contribution is that a deducing method for determining the relationships between the shape and scale parameters of Gamma processes and accelerated stresses was presented. When predicting the lifetime of an individual, Bayesian inference methods were adopted to improve the prediction accuracy, in which the conjugate prior distribution and the non-conjugate prior distribution of random parameters were studied. The conjugate prior distribution only considers the random effect of the scale parameter while the non-conjugate prior distribution considers the random effects of both the scale and shape parameter. The application and usefulness of the proposed method was demonstrated by the accelerated degradation data of carbon-film resistors.

关键词： conjugate accelerated prior lifetime Bayesian determining illustrated likelihood acceleration fitting