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2012 Vol. 38, No. 4

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Adaptive tracking control method for nonlinear trajectory
Miao Cunxiao, Fang Jiancheng, Sheng Wei
2012, (4): 427-431.
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For flight trajectory tracking accuracy and quality problem of small unmanned aerial vehicle (SUAV), an adaptive tracking control method for nonlinear trajectory was proposed. Waypoints were fitted utilizing five-order B-spline to built nonlinear desired trajectory. The location and crossing heading error equations were established within the Serret-Frenet coordinates. The asymptotically stable convergence adaptive crossing heading law was designed based on the error formulations. The flight experimental results show that the proposed adaptive tracking control method are effective and can improve the tracking accuracy.
Design and working mode analysis of dissimilar redundant actuator system
Fu Yongling, Pang Yao, Liu Hesong, Wang Lijian
2012, (4): 432-437,443.
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The dissimilar redundant actuator system gets rid of central hydraulic power and avoids the common fault effectively, which is consistent with the development trend of more electric aircraft. Based on the load characteristics matching method, a dissimilar redundant actuator system made of electro-hydrostatic actuator with variable motor speed and electro-mechanical actuator was designed. The overall mathematic model was established by considering both of the air load and connecting stiffness of control surface. Then three typical operation modes were analyzed theoretically and simulated contrastively, and the switch transience between these operation modes under the air load was presented, too. Meanwhile, the zero current control method in the current loop of motor was proposed to the no-load operation mode. Its controller was simple to realize and the switch was rapid and reliable. The analysis results provide the theoretical evidence to system design, operation mode and fault switch method of dissimilar redundant actuator system.
Three solution models of lateral frequencies of stiffening cylindrical shell
Xing Yufeng, Pan Zhongwen, Yang Yang
2012, (4): 438-443.
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The equivalence methods of area and moment of inertia were studied for the stringers in stiffening cylindrical shell, and the accuracy of moment of inertia when the area was equivalent, and the accuracy of area when the moment of inertia is equivalent were investigated respectively. The concept of critical thickness of thin cylindrical shell was revealed in the calculation of lateral inherent frequencies and the deficiency of the equivalence thickness method was pointed out. The equivalence beam model, the three dimensional (3-D) shell-beam model and the 3-D varied thickness shell models were presented for the lateral free vibration analysis of stiffening cylindrical shell, although these models can be utilized to analyze the dynamic characteristics of rocket, the lateral effects of the stringers predicted by different models differ greatly. Moreover, one dimensional analytical solutions corresponding to both 3-D models with simply supports were given, from which the effects of stringers on the lateral frequencies were straight forward.
Detection of the number of sources using peak-to-average power ratio modified by Gerschgorin radii
Jiao Yameng, Huang Jianguo, Hou Yunshan
2012, (4): 444-448.
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Aiming at solving the problem of improving detection ability of unmanned underwater vehicle. An information criterion for source number detection with the peak-to-average power ratio modified by Gerschgorin radii (PGAIC) was proposed. The method first employed eigenvectors of the sample covariance matrix to weight the received data and calculated the peak-to-average power ratio, then took a Gerschgorin transform to the sample covariance matrix, next the new peak-to-average power ratios modified by Gerschgorin radii were introduced to Akaike information criterion(AIC) with the transformed covariance matrix. Simulation results show that PGAIC method is superior to conventional detection methods such as AIC and minimum descrition lengh(MDL) at lower signal to noise ratio, not affected by the intensity difference between the targets.
Comparison of experimental ground testing and computational fluid dynamics for S-shaped inlet and JT15D-4 engine
Li Dawei, Ma Dongli, Chen Xiaolong
2012, (4): 449-452,458.
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The S-shaped inlet working with the turbofan engine was discussed by using ground test and computational fluid dynamics (CFD) codes. A full scale S-shaped inlet model had been made of glass fiber reinforced plastic. The model was installed in front of the JT15D-4 turbofan engine, with the results obtained from the full scale matching ground test at Beijing. Static pressure,total pressure recovery and total pressure contours were presented. Under the same working condition, the performance of the S-shaped inlet was developed by using CFD codes. Based on comparison of CFD code to full scale measured test data, they match well. It means that on one hand the S-shaped inlet was designed properly according to the engine and they can match work together, on the other hand the CFD codes are shown to predict total pressure contours at the duct exit accurately, the CFD codes could be used for the inlet design.
Method of missile tracking in images based on ordered weight residual resampling particle filter
Zheng Hong, Sui Qiangqiang, Sun Yuquan
2012, (4): 453-458.
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There were many problems existing in the missile alarm and tracking for aircrafts, such as 2D missile motion modeling, the nonlinearity of the motion model and the non-Gaussian of the interference. The motion pattern of the proportional navigated missile from the 3D space to the camera imaging plane was studied and the motion model of the 2D projection of the proportional navigated missile was established. Since the velocity and acceleration in the model was non-linear, and the random interference (e.g., wind direction, wind power, cyclone, air flow) encountered by missiles was also non-linear, the particle filter was used to track missiles. As for the particle degeneration problem in the tracking procedure, the ordered weight residual resampling particle filter (OWRR-PF) method was presented to release the particle degeneration problem and improve the tracking accuracy. Experimental results demonstrate that the tracking accuracy by using OWRR-PF method was improved by 70% than the standard particle filter, and 15% than the residual resampling particle filter.
New system calibration method for strapdown inertial navigation system
Zhang Huaqiang, Zhao Yan, Chen Yu
2012, (4): 459-463.
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Focusing on different types of strapdown inertial navigation system (SINS) having great difference on measuring range and dynamic performance, a novel SINS calibration method using centrifuge and turntable was proposed. The turntable was installed on the centrifuge. By adjusting the attitude of the turntable and the control parameter of the centrifuge, signals of different ranges and dynamic parameters would be generated, and this could be used for calibrating different SINS. The complete control models of the centrifuge and turntable were built and simulated. The SINS was rotated 12 times in six positions, and then 24 error parameters of SINS would be determined. The theory analysis shows that the new calibration method is simple and easy to be implemented, the calibration data has high-usage, and the output signals can be set flexibly. Therefore this method has some actual engineering value.
Parameter identification of diesel fuel injection system model using genetic algorithms
Li Runing, He Yongling
2012, (4): 464-467,472.
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The changing of pressure in the diesel injection system results in the growth and collapse of gas bubbles, which affects the diesel flowing and pressure. In order to predict the initial void fraction and changes in the diesel injection system, the method using improved genetic algorithms in parameter identification for the model of diesel injection system was presented, including the initial void fraction of plunger chamber, delivery valve chamber, high-pressure oil pipe and needle valve chamber. The model of diesel injection system under the condition of gas-liquid was established based on the gas model, fitness function was built by comparing with the simulation results and the experimental data, so the parameter optimization of the model of diesel injection system was realized, and the model of diesel injection system of parameter identification was carried out. Comparisons between simulation results and experimental data show that the improved genetic algorithms are capable of estimating unknown parameters in the model of diesel injection system.
Fast-convert ultrasonic frequency pulse GTAW arc behavior
Yang Mingxuan, Qi Bojin, Cong Baoqiang, Li Wei
2012, (4): 468-472.
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Based on ultrasonic frequency pulse gas tungsten arc welding(GTAW) power, the out current with di/dt≥50A/μs for the ultrasonic fast current rate of rise and fall was achieved. The arc behavior was investigated in the use of ultrasonic frequency pulse tungsten inert-gas welding for 0Cr18Ni9Ti stainless steel, including the electrical characteristics of arc, the arc force and welds penetration rate. The experimental results show that compared with conventional direct current GTAW, arc plasma has an obvious pinch effect, and the arc force a huge increment with the effect of ultrasonic frequency pulse current. Similarly, the weld penetration of ultrafast frequency pulse GTAW could be improved with enhance of the arc force as the increasing depth of penetration and the decreasing weld width. It is beneficial to improve weld quality and effectively to achieve perfect welds of 0Cr18Ni9Ti stainless steel.
Ionosphere hybrid modeling method for short-wave ray tracing
Li Weimin, Su Donglin, Yan Zhaowen, Liu Yan
2012, (4): 473-477.
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Based on the international reference ionosphere (IRI) and the quasi-parabolic segments (QPS) model, a new ionosphere hybrid modeling method for short-wave ray tracing was proposed. The group ranges which show the short-wave propagation trace in the ionosphere were obtained separately by simulation in the hybrid model and the IRI model. By comparing the simulated results and the ionospheric oblique incidence sounding experimental data, the hybrid modeling method accuracy at mid-latitude region in China was analyzed. It indicates the ray tracing simulation accuracy in the hybrid model on experimental day better than the one in the IRI model. The limit to the QPS model-s input is reduced by the hybrid modeling method and the QPS model-s application range is extended in ray tracing technology.
High precision calibration method for three-cluster FOG
Zhang Xiaoyue, Yang Gongliu, Zhang Chunxi
2012, (4): 478-481,486.
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For three-cluster fiber optic gyro(FOG), calibration model was defined. The calibration error induced by earth rotation and interference among various parameters was analyzed theoretically. A high precision calibration method was presented, in which every parameter was tested separately, including bias, scale factor and misalignment. The calibration method was applied in a three-cluster FOG strapdown inertial navigation system(SINS), and the calibration result was given out. Error test for calibration result and SINS static test, dynamic test was carried out. The test results show that expected precision both of FOG and system performance have been achieved, the availability and utility of the calibration method are validated.
Transmittance measurement system based on triple-junction solar cells
Zhao Huijie, Tang Wu, Zhang Ying, Zhang Qingxiang
2012, (4): 482-486.
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The degradation of solar cells’ coatings in space environment will shorten space aircraft’s fight life. So the research of the system which can measure the coatings transmittance’s change is important. The transmittance measurement system was constructed by two triple-junction solar cells, one of which was covered with the glass sample and another was not. The triple-junction solar cells were used as detectors to measure solar flux. The photocurrent measurement circuits convert the photocurrent to analog volt, which will be multiplied and filtered. And the volt was translated to digital signal, which is transferred to the computer finally. The photocurrent signals of two triple-junction solar cells were acquired to calculate the overall transmittance in the solar cell responding spectrum, by using two channels comparing measurement method. The solar cells operation temperature was monitored by platinum-chip temperature sensors, in order to avoid measurement error which is induced by temperature change. The measurement relative error of system is about 0.1%, and the measurement uncertainty is less than 0.15%, which is proved by experiment.
Application of hybrid rocket motor on manned lunar landing
Zhu Hao, Tian Hui, Cai Guobiao
2012, (4): 487-490,496.
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A primary optimal design of manned lunar ship with hybrid propulsion system was proposed. After researching on the manned lunar plans of the main space industry countries and regions and analysis of "Apollo" lunar module, based on hybrid rocket motor system design model, a genetic arithmetic was used to optimize the hybrid rocket motors substituting the descent and ascent liquid rocket motors of "Apollo" lunar module. The comparison and analysis of their function, mass, volume and propellant characteristics show that it has great advantages and application prospect for hybrid propulsion technology to be used in manned lunar ship and deep space exploration.
Method of transfer alignment of distributed POS for airborne remote imaging
Gong Xiaolin, Fang Jiancheng
2012, (4): 491-496.
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Aiming at the precision alignment of distributed position and orientation system(POS) for airborne remote imaging, the errors which affect the transfer alignment accuracy and velocity were analyzed and the real circumstance of remote imaging was considered. Based on these, a transfer alignment method of distributed POS which uses the climbing course of aircraft was proposed and compared with other maneuver modes. The semi-physical simulation shows that good alignment accuracy can be obtained and the moving condition of aircraft is used efficiently. The investigative results would offer the principle foundation for design and choice of the alignment schemes of airborne distributed POS.
Analysis on effect of mental workload on preattentive processing
Wanyan Xiaoru, Zhuang Damin, Liu Wei
2012, (4): 497-501.
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To investigate the effects of mental workload related to flight task on the preattentive processing, 14 subjects performed a flight simulation task under different mental workloads, and the mismatch negativity (MMN) was recorded as evaluation index. The subjects were asked to perform the whole process of flight simulation in a flight simulator, including take-off, cruise and landing. During the flight, subjects were instructed to keep monitoring the information targets presented on the head-up display and respond to any abnormal information. The mental workloads were manipulated by setting the quantities and refresh frequencies of the information targets. The experiment results reveale that the frontal-central MMN is affected by mental workload significantly. The present study can offer electrophysiological reference for flight mental workload assessment in complex tasks.
Similitude investigation for ground experiment of spacecraft
He Zhaowei, Shi Peng, Ge Bing, Zhao Yushan
2012, (4): 502-508.
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The similitude problem for ground experiment of spacecraft was investigated. Dimensional analysis was revisited and employed to develop the necessary similarity conditions, and the constraints on the application of these similarity conditions were also discussed. The activity analyses of the states were proposed based on bond graph, furthermore, a continuous metric that could quantify the proximity of a given model to exact similitude was developed. The viability of this metric was demonstrated using two case studies, one focusing on two-body motion simulation and the other focusing on relative orbit motion simulation. Numerical simulation results prove that the method can be used to quantify the degree to which the model is close to satisfying the exact similitude quickly and effectively at engineering analyses.
Analysis of tail-slaps of supercavitating vehicle influenced by distortion of cavity shape
He Qiankun, Wei Yingjie, You Tianqing, Zhang Jiazhong
2012, (4): 509-512,518.
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The tail-slaps of supercavitating vehicle and the distortion of cavity shape are coupling with each other. The coupling motion equation of supercavitating vehicle was established and the tail-slaps of the vehicle influenced by the distortion of cavity shape were also analyzed in different conditions of velocity and initial angel velocity. The research results show that the vehicle-s rotating angel, movement cycle, lift force of tail-slaps and drag force of tail-slaps increase by the effect of the distortion of cavity shape. In different velocities, the vehicle-s rotating angel, movement cycle and tail-slap cycle, which are influenced by the distortion of cavity shape, decrease by the increment of velocity. In different angel velocities, the vehicle-s rotating angel, movement cycle and tail-slap cycle, which are influenced by the distortion of cavity shape, increase by the increment of angel velocity.
Combined simulation system design for trajectory planning of spacecraft proximity guidance
Liu Tao, Zhao Yushan, Shi Peng, Li Baojun
2012, (4): 513-518.
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Aiming at simulating and verifying trajectory planning for spacecraft proximity guidance, a combined simulation system based on Visual C+ +, Vega Prime and Matlab was developed. The mathematical model of the problem was presented. Then the model was solved and optimized using Matlab, and the position and velocity as well as other information of the chaser spacecraft doing proximity maneuver were obtained. The models of satellites and other objects were built using Multigen Creator software, and Vega Prime was used for visual simulation. After that, system integration was constructed via Visual C+ +, and the simulation and verification system based on Visual C+ +, Vega Prime and Matlab was built. The verification of this combined system was discussed using a test case that the fuel-optimal trajectory based on continuous thrust was planned for proximity rendezvous for elliptic reference orbit.
Error auto-compensation technology of inertial navigation system based on double-axis rotation
Yang Guoliang, Wang Wei
2012, (4): 519-524.
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To solve the problem that the gyro drift decreased the long-time navigation accuracy, a new auto-compensation scheme with double units was put forward. The constant gyro drifts could be modulated in all directions by continuous rotation, so as to improve the accuracy of the inertial navigation system greatly. The error characters of system errors were analyzed, such as constant gyro drift, scale coefficient error, installation error and angle random walk. The influence of rotating mechanism precision on the modulation performance was also demonstrated. Multiple sea tests were operated by the double-axis rotary laser strapdown inertial navigation system which was self-developed. The results show that the scheme is efficient and the accuracy of the system can be improved by one order of magnitude while the precision of the inertial components is unchanged.
Hybrid reliability analysis method based collaborative optimization
Wang Xinghao, Ma jiming, Zeng Shengkui, Zhao Xuemei
2012, (4): 525-528,534.
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The reliability analysis in the multidisciplinary design optimization (MDO) process causes great computational cost. Aiming to this problem,two kinds of existing reliability analysis methods were integrated into the collaborative optimization(CO), and hybrid reliability analysis based CO method was proposed. This method analyzes the reliability in the subsystem of CO model, and before each reliability analysis, the distance between the iteration point and constrained boundary was estimated. For the point near the constrained boundary,the first order reliability method was applied to analyze the reliability, while the mean value method was applied to analyze the reliability approximately for the other points to reduce the unnecessary analysis cost, then this hybrid reliability analysis process was integrated into the CO framework. Experimental results show that the hybrid reliability analysis based CO method improves the optimization efficiency without decreasing the accuracy of reliability and it has practical significance for engineering application.
Multi-excitation source united controlling test method based on distributed actuation
Yao Jun, Wu Yanfei, Yao Yihong
2012, (4): 529-534.
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In view of the questions of high-speed aircraft withstanding complicated vibration environment, their vibration durability could not being plenary examined by existing vibration test technology, a vibration test technique integrating piezoelectric element, vibration table, exciter was proposed, the vibration table and exciter placed on the large-stiffness part of the structure to provide concentration force and piezoelectric elements on the small-stiffness part to provide distributed force. The vibration environment dimension of high-speed aircraft and its influence to the failures of high-speed aircraft were analysed. Based on the research on the material and actuation dimension of the piezoelectric element, the feasibility of piezoelectric element used as the distributed excitation source in vibration test was analysed. Last, a test demonstration system was constituted and a serial of test items were carried out. Using this method, the RMS magnitude of one point on the flexible part of the structure can be controlled to 20.8g. The rationality and the extensive engineering application potential of this technique are verified by the test results.
Static modeling method and characteristic analysis of exception propagation network
Qiu Xiang, Zhang Li
2012, (4): 535-540.
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In area of the exception handling, exception propagation is of catholic concern. Previous researchers focused more on exception propagation paths and the source of a thrown exception but ignored the networked characteristic of exception propagation. An exception propagation networked model was proposed based on the definition of exception transitivity relationship between two methods. A case study was presented for the analysis of main characteristics of complex network, which includes the degree distribution, the exception hierarchy distribution, the clustering coefficient and the average shortest path. The results show that the in-degree and out-degree distribution are basically subject to a power law distribution; Most exception propagation processes violate the rule of "Do not spread the abstract exception"; The exception propagation network appears the low cohesion feature due to the "Weak Border" characteristic. These empirical findings can provide the guidance for software developers in the design process for exception handling.
Swarming aircraft collaborative localization based on mutual rangings
Liu Juncheng, Zhang Jingjuan, Feng Peide
2012, (4): 541-545.
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In the environment of net-centric war, collaborative localization based on mutual rangings is proposed to improve the inertial positioning accuracy of the swarming aircraft when global positioning system (GPS) is unbelievable. The collaborative localization system, which was mainly composed of the inter-flight data link and the inertial system, was designed and the ranging scheme as well as the time synchronization problem were analyzed. The polygon translation-rotation method was applied to estimate the inertial positioning errors. Simulation results show that the polygon translation-rotation method slows down the divergence speed of the inertial positioning errors effectively and the inertial navigation accuracy is about 2 times of the original level with the help of collaborative localization for the five aircraft swarming.
Method based on network flow simulation for sneak circuit analysis
Zou Tao, Ma Qishuang
2012, (4): 546-550.
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To solve the too many constraints problem in sneak circuit analysis of clue table method, network flow simulation was applied in sneak circuit analysis based on the research of artificial neural network (ANN) analysis method. Electrical elements- qualitative simulation models were established and circuit network-s composition method was determined, based on electrical and ANN characteristics. The network flow simulation method simulated the current diffusion process and predicted the loads- responses in circuit network. The analysis results showed whether there was sneak circuit problem. Compared the loads- responses between the circuit network design and simulation analysis forecast, the difference was the sneak circuit problem. By using this method, the loads- responses in circuit network can be predicted correctly, the defects of the clue table method can be overcome, the analysis requirements of known conditions and the effects of human factors on the analytical results can be reduced. The sneak circuit problems in real circuit network can be solved effectively by this method.
Trajectory of a spacecraft with constant radial thrust
Zhang Hao, Shi Peng, Zhao Yushan, Li Baojun
2012, (4): 551-556.
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The trajectory of a spacecraft under constant radial thrust was studied. Great deals of efforts were dedicated to investigate the boundedness and periodicity. The case of elliptic parking orbit was focused. First, the equations of motion were formulated in polar coordinates and simplified into quadratures by using of energy integral and angular momentum integral. Then, the orbital boundedness was analyzed by transforming the original problem into solving a cubic inequality. Basing on different initial parking true anomaly, the problem was researched separately. The bounds of motion and escaping conditions were obtained in terms of thrust. Next, the periodicity of motion was studied by utilizing elliptic integrals. The periodicity of radial motion and periodicity in polar angle changing were explained. A property of quasi-periodicity in motion was described. The quasi-periodic motion could degenerate into periodic orbits, if a condition among initial parking parameters and thrust were satisfied. Meanwhile, a Newton-Raphson algorithm was given to obtain periodic orbits numerically. Several numerical examples were given to support the conclusion.
Buckling analysis and experiment of open cylindrical thin shells under axial load
Zhang Zhanzhi, Zhao Guowei, Huang Hai, Huang Chengjing
2012, (4): 557-562.
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The axial load-bearing capacity and stability of open cylindrical thin shells is a key point in the mechanism design of storable tubular extendable member (STEM). Based on eigenvalue buckling analysis, the relationship between the buckling loads and the design parameters of open cylindrical thin QBe2 shells with two ends clamped was studied. And a buckling load model was built by the power functions fitting method. To validate the eigenvalue buckling analysis method and the buckling load model, axial compression experiments of open cylindrical thin shells made from QBe2 were conducted. The experimental results indicate that: the eigenvalue buckling analysis method can be used to analyze the axial load-bearing capacity and stability of open cylindrical thin shells of isotropic material with two ends clamped; the maximum error of the buckling load model is 21% in calculating the buckling loads of axially loaded open cylindrical thin shells of isotropic material with two ends clamped.
Investigation and enhancement of hole mapping method
Yuan Wu, Yan Chao, Xi Ke
2012, (4): 563-568.
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In order to reduce the storage of the traditional hole mapping method, a minimum hole mapping algorithm was presented which expands the concept of closure. Wall surface was allowed to terminate on truncation surface of grids, which would efficiently reduce the area of hole mapping and save the storage. Methods of hole mapping cell identification suitable for the generalized closure were analyzed, showing the unreliability of using wall surface information to identify the property of hole mapping cell. A new method named Inverse mark was developed which is especially suitable to the generalized closure. Mesh nodes- information was used to automatically identify out points, which are initial points to advance inside of the grid region. Results show that Inverse mark is of great efficiency, good reliability, and high automation, and can effectively enhance the flexibility of chimera grids to local complex configurations such as slits.

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