Abstract:In order to find the best synthetic jet model for study of active flow control numerical simulation, outlet velocity model, single link domain model and dynamic boundary model are researched through solving the two dimensional transient reynolds average navierstokes (RANS) equations under consistent grid and boundary conditions. Three models all show good capability of capture synthetic jets' velocity. The dynamic boundary model in which the spatial distribution and time distribution of diaphragm motion are considered and the volume change rate of actuator cavity is included can accurately capture the distribution and intensity of vortices. So the dynamic boundary model is an ideal model for applications.

Abstract:The safety of carrier aircraft and rocket is the foundation of inner air launch system. Linear theories with small disturbance and timedomain method are applied to study the stability、flying quality and safety during separation in cabin, and some ways are brought forward to improve flying quality. It is considered that rocket is likely to hit aircraft and the effect of carrier aircraft's pitch angle and rocket's location are simulated by using the kinematics equation of rocket. Through explosion comparability theory, the influence of rocket explosion wave on aircraft and pilot is taken into account and safe distance is obtained. The results of qualitative and quantitative analyses provide a theoretical basis for the application of inner air launch system.

Abstract:In this paper, a new way to model the Hypersonic Aircraft via the analysis of the movement characteristics and modeling difficulties of the targets is put forward. In different moving phases of the aircraft, the idiographic models of each phase consulting the normal aircraft, ballistic targets, cruise targets and orbiting targets are summarized respectively. Furthermore the simulation of reentry phase of X-37B is given, the simulation result verifies the validity of the model.

Abstract:With the rapid development of the air transportation，air traffic will become heavier and heavier, establishing air highway is important to alleviate the increasingly serious problem of air traffic congestion. This paper gives a basic concept of air highway and of ramp, using the basic theory of cell transmission model to present an air highway ramp flow control model. By solving this model, the system minimum time, system clearance time, optimal flow distribution of ramp, and so on are obtained. Results of a case study show that this model can meet the modeling demand of air traffic highway ramp flow control, and also can describe the dynamics feature of traffic flow in air highway system.

Abstract:The mathematical model of plasma flow control is established by regarding the influences of the plasma aerodynamic actuation on the fluid as body force and thermal energy and considering the influences of the plasma temperature rise on the thermal physical property of fluid. The body force and thermal energy profile function obtained by solving the potential equation and the charge equation and the thermal physical property function obtained by fitting experimental data are added to the Navier-Stokes equation as source terms and coefficient respectively. Simulation investigation of flow separation control on a compressor cascade by plasma aerodynamic actuation is performed under low velocity conditions. The influence of the flow velocity, incidence and the intensity of plasma aerodynamic actuation on the performance of compressor cascade is investigated. After actuation in the case of [WTBX]Ma[WTBZ]=0.05 at an incidence of 2°,the location of separation point is moved from 65.09% to 79.4% of the chord, the flow turning angle is increased about 1°, the maximum total pressure loss coefficient is reduced about 7.4% and the width of the trail is reduced about 12%. The actuation effect is reduced with the increase of air flow velocity. The change of incidence affects the actuation effect. The actuation effect is obviously improved with the increase of the intensity of plasma aerodynamic actuation.

Abstract:The SEA model of hypersonic aircraft X-43A is established based on statistical energy analysis (SEA) theory. Three parameters of the SEA model are established by the theory and experiential formula. According to the damping loss factors of model subsystem and the acoustic absorptivity of cavity, sensitivity analysis of vibro-acoustic response is discussed. The effect of vibro-acoustic response caused by the division way on plate subsystem and material structure are analyzed. The analysis results show that the material structure, damping loss factors and material type have a great effect on the characteristics of vibro-acoustic response. The division way of plate subsystem can affect computational accuracy greatly. The influencing factors should be synthetically considered in the design of acoustics structure.

Abstract:The outputs of complex simulation system are characterized by complex, nonlinearity and smoothness. Great risks come into existence when the traditional model validation method is used to solve the above problems. Complexity measure is an important parameter in describing the characteristic of nonlinear time sequence，so the theory of complexity measure is introduced into simulation model validation. Based on calculating the complexity of experiment and simulation data, the validity of model is measured by comparing the complexity measures between the simulation results and experiment data. Finally, an example is given to analyze the conclusion. The result shows that the method is simple in computation， practical and without any special requirement to the length and stationarity of time sequence.

Abstract:Aiming at the problems that the former lid of the missile was easy to be broken by high temperature and high velocity jet flow, by computing sinkage of the whole body and head part of missile, depending on method of computational fluid dynamic, the surface pressure and temperature is analyzed on different missile pose and leave distance. The result of simulation shows the parameter of the former friable lid exits great difference, the conclusion is important to design launch box in the engineering application.

Abstract:The typical problems in present-day large-scale operation simulation system such as the reuse and interoperation of the models, fast constitution of simulating application and expansibility are analyzed. Based on the ideas of SOA and EDA, an event-driven service-oriented architecture of operation simulation integration platform is designed, the run-time flow of event-driven service-oriented simulation is given, and the attribute of the architecture is analyzed.

Abstract:Laser imaging fuse has a strong anti-stealth and anti-electromagnetic interference capacity. In the application of laser imaging fuse to air-to-air missile the design problems of fuse front rake and fuse detection range have to be solved. Based on analyzing the principle of the push-broom method laser imaging fuse, the measurement model of laser footprint size and the mathematic model of fuse front rake and fuse detection range are established. The design criterion of fuse front rake and fuse detection range and their relationship to fuse-warhead match by simulation in variety conditions are acquired, which provide a reference in theory to the application of laser imaging fuse in air-to-air missile.

Abstract:Although the traditional LMS algorithm has many advantages, such as simple methods and small burden in computation，but for the sake of constant step, it is always into contradictions in the relationship between solving the steady-state error and convergence. Based on brief discussion of fixed step-size LMS, and the principle of adjusting step-size for variable step-size LMS algorithm, by constructing a nonlinear function between the step factor and the error signal , a new variable step-size LMS algorithm based on sine function is proposed, along with the performance analysis with regard to different parameters. The theoretical analysis and simulation results show that the convergence speed and steady-state error of this algorithm are better than those of the fixed step-size LMS algorithm and SVS-LMS algorithm.

Abstract:To advance the system campaign efficiency for air defense weapon system located on the ground, based on the technique characteristic and the good mutual complementation for active and passive radar in new weapon system, a synergistic work model for active and passive radar is put forward. Moreover, based on the superiority of interactive multi-model (IMM) algorithm and unscented kalman filter (UKF) in dealing with the strong maneuvering target and the nonlinear filter problem, and considering the real-time requirement for tracking system, a self-adaptive IMM-UKF algorithm is put forward and designed. Through the Monte Carlo simulation, performance of it has been improved compared to that of work alone model, and the results demonstrate that the synergistic work model and the updated algorithm are effective and superior.

Abstract:Directional antenna technique is adopted to enhance the outage performance of cooperative communication. Protocols which are suitable to bidirectional single relay AF cooperative communication based on directional antenna is proposed on the basis of the traditional Protocols and the outage probability low bound of TR-BF TDBC and OSS systems are derived theoretically. Simulation results show that the derived low bound and the exact value are very tight when SNR is high or the channel coefficients from two ends to relay vary widely. The outage performance of OSS is better than that of TDBC，and the outage performance of TR-BF AF cooperative communication is better than that of the traditional one when spectral efficiency is not very high. Usually, the outage performance of cooperative communication system with full directional mode is improved, and OSS protocol should be adopted as far as possible in practical applications in order to fully gain best of its advantages.

Abstract:In order to solve the problem of wireless network formation efficiency optimization and evaluation based on aircraft onboard directional antenna, a quantification evaluation model is proposed considering the particularities requirements of war-craft wireless network application. The use of the model firstly defines the network formation, analyzes the factors of network formation efficiency, then picks up evaluation indexes of transmission speed, time delay, network robust, stealth and special data link requirements, followed with respective quantification formulas for each index. Finally, a given network example is defined and evaluated using the model. Experiment shows that the network efficiency evaluation model proposed in this paper is effective and feasible.

Abstract:In order to achieve relative orientation and scale values between environmental information and reference information for path integration of UCAV cognitive navigation, a method based on iterative least-squares is proposed to solve high-precision similarity transformation parameters. SURF algorithm is used to extract high robustness feature points, then ratio method is taken to purify the matching pairs to get a point-to-point set, the elements in the set are further transformed into vectors, similarity transformation parameters are gained by iterative least-squares algorithm, then the perceived image's orientation is rotated backward, and the scale is adjusted inversely according to the gained parameters, circulate the operations until relative orientation and scale value are finally obtained. The simulation results show that the use of the above method can get high-precision orientation and scale parameters and anti-noise performance is superior to the least squares algorithm.

Abstract:Safety application is very important in vehicular ad-hoc networks. Safety-related message priority is classed based on message urgency. In this paper, a spatiotemporal-based dynamic priority scheduling scheme is proposed. A spatial-temporal relevance function is introduced to represent the priority, which decreases as distance and duration increase in the message dissemination. Meanwhile, the distribution of a urgency message is limited to a bound duration and spatial area. Analyses and simulations show that the spatiotemporal-based dynamic priority scheduling is of a significant performance improvement in decreasing the network load in high density and increasing the transmission distance in the low density over the method using the fixed priority with the maximum delay threshold.

Abstract:For the problem that TACAN airborne equipment is huge in analog system and that the calculating method of TACAN bearing signal is complex in calculating process and low in precision ,this paper presents an accurate method of calculating the bearing settlement using Kalman filtering distill envelope signal based on the ideal of software radio and IF digital processing .Firstly, this paper adopts the method of state space description to derive in detail the expressions of various parameters in the observation equation and state equation of envelope signal, then, designs the Kalman filtering model of distill envelope signal，extracts the envelope signal process and the method of calculating bearing. Finally, the experiment result of equipment simulator shows that the designed method is simple in process, accurate in calculating bearing precision and is applicable to the practical equipment.

Abstract:As for the existing neural network algorithm，a new kind of optimized BP neural network algorithm is put forward and applied to network quality evaluation. In the optimization scheme, the stages of rise and fall are optimized by adopting different strategies.The theoretical analysis shows that the use of the optimized algorithm can overcome the previous shortcomings of slow weight convergence and shaking problem in error convergence .The experiments show that the use of the optimized algorithm will decrease the learning error of neural network and the quality classification error obviously, and simultaneously improve the accuracy of the evaluation significantly. The error of the optimized algorithm is more stable than that of the traditional algorithm during the process of convergence. As the result, the learning error falls by 9.64% and the decline of quality classification error is 23.1%. Compared with the traditional and step size variable algorithm, the use of the optimized algorithm raises the checking accuracy rate separately by 19.65%and 9.88%. It's obvious that the optimized algorithm is effective in raising the prediction accuracy of the BP neural network by a large margin.

Abstract:Based on basic theory of cyclotomic coset, the concepts of decomposition of defining sets for binary and quaternary BCH codes are introduced respectively this decomposition of defining sets builds up a bridge among the Euclidean orthogonal decomposition of binary BCH codes and Hermitian orthogonal decomposition of quaternary BCH codes. Then the orthogonal decomposition of the dual codes of binary and quaternary BCH codes is also presented. Furtherly, the decomposition of the defining sets of primitive binary and quaternary BCH codes with given designed distances is well studied and solved. Applying the results, some entanglement-assisted quantum codes with good parameters are constructed. The method proposed in this paper devised a new scheme in determining the optimal number of entangled bits, which can simplify the theoretical derivation in constructing entanglement-assisted quantum error correcting codes from classical BCH codes, and also be useful for studying general constructions of entanglement-assisted quantum error correcting codes from cyclic codes.

Abstract:The blast load is very important to the construction of underground rock engineering and the defense engineering project. The study on underground structural failure modes under blast loading is always a hot problem. The underground structure is developing to big span direction. But so far, the study of big-span deep underground structure's dynamic response is seldom. The structural mechanics under blast loading is still not known well. So，the nonlinear dynamic finite element procedure of ANSYS/LS-DYNA is used and the fluid-solid coupling algorithm is selected to study the dynamic response of underground structure with different spans. The explosion is closed and the detonating distances are changed. The analysis shows that the mechanics status of big-span is complete changed compared to the small-span one. And also the maximum stress curves of structures with different spans are obtained.