Table of Content

31 August 2012, Volume 46 Issue 08 Previous Issue    Next Issue

Communication and Transportation

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Introduction of a Novel HeavierThanWater Autonomous Underwater Vehicle and the Analysis on the Advantages YAN Hui, GE Tong, WANG Biao 2012, 46 (08):  1173-1177.  Abstract ( 2698 )   Save A novel heavier-than-water AUV（HTW AUV） was introduced. This kind of autonomous underwater vehicle (AUV) has negative buoyancy and bears the residual gravity with its wings, for this reason the space occupied by bulky buoyancy device in the negative buoyancy vehicle could be saved to enhance the velocity and reduce the cost of it. The new design concept and the primary components were outlined and introduced. Based on it, the advantages of the HTW AUV were analyzed through comparing the data from the wind tunnel test with that of the traditional AUV. The comparative results show that this novel AUV has a lot of merits. At last, the possible applications of the HTW AUV were given. The novel type AUV would be used more widely after some key problems had been solved. References | Related Articles | Metrics

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Study on Resistance Performance of Working Ship with Notches Based on CFD SHI Xun, CHEN Xin-Quan, TAN Jia-Hua 2012, 46 (08):  1178-1183.  Abstract ( 3429 )   Save Variance of ship resistance caused by notches in working ship was studied based on CFD method. By numerically simulating the viscous flow around a series of working ship models with notches, the effects of the variation of notch size in bow in longitudinal and transverse direction, the variation of notch size in stern in longitudinal and transverse direction and the interaction of the notches in bow and stern on ship resistance performance at low speed were obtained. Basis for improving the resistance performance of this kind vessel was provided. References | Related Articles | Metrics

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Research on Design of Principal Dimension Elements of Hangar in Aircraft Carriers HU Yu-Long, HUANG Sheng, HOU Yuan-Hang, WANG Wen-Quan 2012, 46 (08):  1184-1189.  Abstract ( 4113 )   Save Hangar is the biggest cabin for maintaining and safeguarding aircrafts in aircraft carrier and the design of principal dimensions of hangar should satisfy the demands of an efficient cooperation between crafts and the ship. A craft automation layout program was compiled according to the principia of compact layout and convenient for transport of crafts. And a fuzzy modeling technology was also used to handle those subjective constraints and goals in the design process. Meanwhile, a double optimization configuration was presented to solve the problem of design of principal dimensions. Then, the example proves the validity of the model, as well as a more efficient design strategy , so the method can provide a reference for the design of principal dimensions of hangar in our own aircraft carrier. References | Related Articles | Metrics

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A Roll Damping Prediction Method of Three-Dimensional Ships Based on CFD Computation YANG Chun-Lei, ZHU Ren-Chuan, MIAO Guo-Ping, FAN Ju 2012, 46 (08):  1190-1195.  Abstract ( 3814 )   Save  Based on viscous flow theory, the simulations of forced roll of Series 60 were carried out by solving Reynolds averaged NavierStokes(RANS) equations with consideration of free surface effect. Roll damping coefficients of threedimensional ship body rolling at various frequencies and amplitudes which moves with and without forward speed were calculated. The influences of ship roll damping due to amplitudes and frequencies were analyzed. Comparisons of the numerical results of ship roll damping with experimental and potential theoretical ones were conducted. It shows that the presented computational method can give quite precise roll damping coefficients, which are better than the ones by potential theory and agree well with the corresponding experimental ones. It is of great significance to further analyze and predict ship hydrodynamic performance in waves. References | Related Articles | Metrics

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Study on Vibration Reduction Design of Steel-Composite Materials Hybrid Mounting for Ships Lv Lin-Hua , YANG De-Qing 2012, 46 (08):  1196-1202.  Abstract ( 3390 )   Save Several mountings, such as steelcomposite material hybrid mounting with/without vibration isolation mass and the steel mounting, were optimized considering the vibration level difference and stress constraints. And the weight of structure is chosen as the objective function. The corresponding structural dynamic optimization mathematical models were established. By introducing the Kriging surrogate programming, the models were solved by multiisland genetic algorithm. The computational results show the steelcomposite material hybrid mounting has better effect than the conventional steel mounting in vibration reduction. The introduction of composite materials plays a key role on vibration. The effectiveness of vibration isolation mass was also demonstrated. The adoption of optimal design method is a necessary means during the design of hybrid mounting. References | Related Articles | Metrics

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Numerical Simulation of Diffraction Problems of Moving Vessels in Numerical Wave Tank FANG Zhao-Zhao-1, 2 , ZHU Ren-Chuan-1, MIAO Guo-Ping-1, GONG Cheng-1 2012, 46 (08):  1203-1209.  Abstract ( 3733 )   Save Numerical simulations of diffraction problem of WrigleyIII advancing with certain forward speeds were carried out in the numerical wave tank (NWT), which is established based on computational fluid dynamics(CFD) method. Regular waves making and propagation were simulated and verified in a reference coordinate system. Wave forces of the retrained WigleyIII advancing in both heading and oblique waves were computed respectively in NWT. Comparison of the present results, the corresponding ones of potential flow theories and experimental one from Delft University of Technology, was made. It shows they agree well each other. The proposed method is of great significance to further analyze and predict hydrodynamic performance of ship and marine floating structures in waves.  References | Related Articles | Metrics

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Dynamic Predication and Analysis on Mooring Maneuver of Ship WANG Fei 2012, 46 (08):  1210-1217.  Abstract ( 3352 )   Save This paper developed a generalized mathematical model on ship mooring maneuver, and used it to predict and analyze the dynamic response of ship in various mooring situations, in which a separate submodel determining the anchor holding force in different conditions was proposed and then formulated in detail. The entire model consists of three parts: the maneuvering motion of surface ship is described by classic MMG maneuverability model, while the underwater mooring chain by lumped parameter method, and the anchor’s dynamics is incorporated into chain through treating it as a mass point at the end of mooring chain because of its small dimensions. At the end, this model was used to predict and analyze the dynamic response of a typical surface ship. The results reveal some valuable conclusions. References | Related Articles | Metrics

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Evaluation of Warship Based on Relative Entropy Method HOU Yuan-Hang, HUANG Sheng, HU Yu-Long, WANG Wen-Quan 2012, 46 (08):  1218-1222.  Abstract ( 2954 )   Save Warship evaluation during the stage of preliminary design presents a complicated decisionmaking problem. A relative entropy method for overall evaluation was proposed, that could present the comprehensive ability of warship. Regarding the opinion integration problem in group decision, the Hadmmard bulge combination was used to concentrate experts’ opinions, and a decision making method with multiple attributes based on entropy theory was introduced for evaluating. So a new decisionmaking method based on entropy theory was formed which supports both group decision and alternatives assessment with large difference. The new method was proved to be practical and efficient by practice. References | Related Articles | Metrics

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Study on Method to Calculate Resistance of Planing Crafts by Combination of “ЦАГИ” Method and RANSE DONG Wen-Cai, YAO Chao-Bang 2012, 46 (08):  1223-1229.  Abstract ( 3874 )   Save Considering the shortage of RANSE & VOF method and semiempirical methods for resistance calculating of planing crafts, a new hydrodynamic equilibrium method, which takes the influence of dynamic sinkage and trim into account, was presented by combination of them. The sinkage and trim are computed by equating the vertical force and pitching moment to the hydrodynamic restoring force and moment. To improve the efficiency, the initial attitudes of planing crafts is provided by “ЦАГИ” method when F>1.5. The present method is found to be efficient in calculating the flow field, resistance, sinkage and trim of planing crafts, and validated by the 46671 and SM5 hull model test data. In a wide range of volume Froude numbers from 0.26 to 6.03, the resistance prediction error is below 7% with a good accordance of sinkage and trim prediction.  References | Related Articles | Metrics

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Study on Wave Loads Characteristic of Pentamaran and the Influence of Sponsons’ Layout WEN Jun-Hua, CHEN Zhen 2012, 46 (08):  1230-1237.  Abstract ( 3114 )   Save Based on the threedimensional potential theory, the waveinduced loads response RAO of the pentamaran, including the vertical shear force, vertical bending moment and torsion moment at the main hull and  the crossstructure sections, was studied. The dangerous sections were derived by the analyses of the distribution of the RAO’s maximum value and the influence of the wave direction. Considering the nonlinear factors, the time history of the wave loads at the dangerous sections with respect to different sponsons’ layouts in irregular wave was calculated, then the significant values of the wave loads amplitude were compared to analyze the influence of the sponsons’ layouts on the wave loads at the dangerous sections, and the optimal arrangement of the sponsons was achieved. Meanwhile, the wave loads were compared with Trimaran. The results demonstrate that the wave loads both on the main hull and crossstructure are smaller when the after sponsons lying at aft quarter length, while the transverse location of the sponsons and the vertical location of the front sopnsons mainly affect the wave loads on the crossstructure, and the existence of the front sponsons can efficiently decrease the wave loads on the crossstructure of the after sponsons.  References | Related Articles | Metrics

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Optimization Design of Hull Lines Based on Hybrid Optimization Algorithm ZHANG Bao- Ji 2012, 46 (08):  1238-1242.  Abstract ( 2623 )   Save In order to overcome the deficiency of simplex optimization algorithm, the optimized design program of ship lines with own intellectual property was developed by combining the genetic algorithm (GA) and nonlinear programming (NLP) method. In the optimization process, the hybrid optimization algorithm was proposed with wavemaking resistance as the objective function, with an appropriate displacement as a basic constraint condition and the parameters of hull form modification function as design variables. At last, the numerical optimization examples for Wigley hull form were provided, which indicates that the result of hybrid optimization algorithm is more excellent than the simplex optimization algorithm in the time and effect. In the preliminary design of a ship, the algorithm can provide the theoretical foundation and technical support for selecting the lines of ships. References | Related Articles | Metrics

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Statistical Analysis on Short-Term Distributions of Wave-Induced Stresses for Container Vessel’s Hull JIN Yong-Xing-a, ZHANG Shi-Bin-b 2012, 46 (08):  1243-1247.  Abstract ( 3245 )   Save  Based on the descriptive statistical analysis for the alternating stress range data，this paper suggests to model the data by a class of normal mixture distributions with two peaks．The parameter of the mixture distribution can be estimated by the EM algorithm. Employing the estimated parameter values of the mixture distribution，some inherent relationships of the fatigue loads in different parts of the hull under certain conditions were revealed．The waveinduced hull stresses are particularly complex at the bow，symmetric normal inverse Gaussian mixture distributions are more suitable to fit the alternating stress range data．The empirical analysis shows that the parameter of the proposed probability distribution can reflect the size of the fatigue loads in different parts of the hull，and the conclusion of inherent relationships of the fatigue loads in different parts of the hull provides a theoretical foundation for the operation quality research of the ship． References | Related Articles | Metrics

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Analysis of the Ship Speed Loss Coefficient Based on Hull-Engine-Propeller Matching and Wave Statistics FENG Pei-Yuan-a, MA Ning-a, b , GU Jie-Chong-a, b 2012, 46 (08):  1248-1253.  Abstract ( 4032 )   Save In order to reduce green-house-gas emission, international maritime organization (IMO) proposed the energy efficiency design index (EEDI) regulation, but has not specified the procedure for calculating the speed loss coefficient. Therefore, this paper aims at analyzing and proposing a calculation process based on hullenginepropeller matching and longterm wave statistics to estimate this speed loss coefficient. The proposed method takes into account the energy transmission among hull, engine and propeller as well as their hydrodynamic interactions; on addition, longterm wave statistics of the ship’s operational regions are adopted as environment input, thus making the current method more objective and realistic. Calculation is performed to a containership in operation and the result is compared with IMO reference value, the regression formula of China ship scientific research center and the widely used NMRI approach. The result obtained by the current method shows the same trend as the NMRI method while being more conservative. Therefore, using the current method to guide ship energy efficiency design can better guarantee the navigation performance of the ship at actual seas. Key words： References | Related Articles | Metrics

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Multi-phase Numerical Simulation of Propeller Turbulent  Cavitation Inception Flow YANG Qiong-Fang-a, WANG Yong-Sheng-a, ZHANG Zhi-Hong-b 2012, 46 (08):  1251-1262.  Abstract ( 3427 )   Save Both of the modified SST turbulence model and BSL Reynolds stress model were used to predict the tip vortex trajectories of E779A propeller under noncavitation and cavitation inception conditions. The vortex core’s minimum pressure coefficient, turbulent kinetic energy, axial velocity component and vortex size distribution related to the trajectory were analyzed at the same time, and the flow physics of tip vortex was presented from the flow field with tip vortex crimp beginning and streamtube formation. The improved Sauer cavitation model accounting for the effects of noncondensable gas’s mass and volume fraction and the bubble initial radius on cavitation inception and the effect of turbulence on phasechange pressure threshold was adopted along with validation of the cavity pattern and area of E779A propeller under lightly, moderately and heavily cavitation levels. The cavitation inception index was determined by the rule of “when σ>σi, the pressure coefficient of the blade tip section is relative unaltered”. The minimum pressure in vortex core on perpendicular cross plane was used to locate the vortex center, and vortex core bound was determined by the peak of turbulent eddy frequency. The results show that a slightly longer tip vortex trajectory appears with the BSL RSM model than the modified SST model as well as a litter bigger local tip vortex cavitation extension and more reasonable turbulent kinetic energy distribution, while the minimum pressure coefficient and axial velocity in blade tip region are smaller. On the other hand, the tip vortex trajectories captured by the two models almost superpose along with nearly the same tip vortex trajectories, minimum pressure coefficient and axial velocity distribution between noncavitation and cavitation inception condition of the two models respectively, which proves that the determination of cavitation inception by the rule is reasonable, and the adopted modified numerical models are appropriate to simulate the tip vortex trajectory. References | Related Articles | Metrics

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A New Method to Calculate Stress Intensity Factor for Parallel Double Cracks CHEN Jing-Jie-a, HUANG Yi-a, WU Zhi-Min-b 2012, 46 (08):  1263-1268.  Abstract ( 2487 )   Save In order to obtain simply stress intensity factors (SIFs) of multi cracks, a new method was proposed to calculate SIFs of parallel double cracks based on maximum crack opening displacement (MCOD) for the double parallel cracked plate subject to uniform tension loads. On the basis of the obtained relationship between the SIFs and the MCOD in the single cracked model, the influences of crack spacing ratios (vertical and longitudinal) and crack lengths ratios were considered, and the function expressions between modified coefficients and vertical spacing ratios were fitted in the different crack lengths ratios conditions when longitudinal spacing ratios is zero. And then, the influences of crack longitudinal spacing ratios on SIFs of parallel double cracks were studied. Finally, an easy way to calculate the SIF of parallel double cracks was presented. References | Related Articles | Metrics

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Threshold Value of Stiffener Bending Rigidity of Transverse Densely Stiffened Plate Under Pure Shear JI Zhen-Hua, WANG De-Yu 2012, 46 (08):  1269-1273.  Abstract ( 2948 )   Save Side shells of bulk carriers composed of transverse densely stiffened plate are subjected to large inplane shearing forces, however stiffener bending rigidity is designed not according to shearing force but according to lateral pressure based on IACS common structural rules for bulk carriers. So it is necessary to investigate the threshold value of stiffener bending rigidity for the stiffened plate under shearing loads. Pure shear buckling strength and ultimate strength of transverse densely stiffened plates with different stiffener bending rigidities were investigated. Then the two kinds of stiffener bending rigidity threshold values were identified respectively when the two kinds of strength of stiffened plate reach the material shear yield limit, which were compared with the calculating value based on AASHTO specifications. The result indicates that the stiffener bending rigidity should be decided by ultimate strength analysis.  References | Related Articles | Metrics

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Research on the Dynamic Characteristics of Laser Gyroscope（Ⅱ） CHENG Yao-Qiang-1a, XU De-Min-1a, 1b , WAN Yan-Hui-2, LIU Ming-Yong-1a 2012, 46 (08):  1274-1279.  Abstract ( 2540 )   Save According to the laser gyro’s phase frequency characteristics this paper analyzed the influence of phase delay on realtime and mobility of missile control system, then studied the factors that cause phase delay of laser gyro, and pointed out that the vibration isolator does not bring phase delay, and FIR filter is the main factor for phase delay of laser gyro.Based on the angle vibration table and inertial measurement unit(IMU) body, four test states were designed and a practical test with phase frequency characteristics of laser gyro was conducted  using sine excitation method. The test results show that the vibration isolator’s delay time is no more than 0.051 ms and the delay time mainly comes from FIR filter, which is in accord with the theoretical analysis results.   References | Related Articles | Metrics

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CAD/CAE Integrated Design of Fin Stabilizer Reinforced Structure Based on Multi-Point Constraint Method ZHOU Qing-Hua, DU Liu-Fa, YANG Xiong-Hui 2012, 46 (08):  1280-1283.  Abstract ( 2885 )   Save According to the complicated characteristic of the ship fin stabilizer reinforced structural design and loads, a CAD/CAE integrated design and analysis method was presented to do three-dimensional structure design, hydro-dynamic analysis and structure property assessment of fin stabilizer reinforced structure. In this research, the multi-point constraint method is adopted to realize the load transfer between two kinds of discordant elements, which simulate fin stabilizer reinforced structure and fin stabilizer foundation, the ship motion response and hydrodynamic pressure are obtained by the free surface Green function method and the three dimensional linear potential flow theory. The key techniques discussed in this research provide a new technical approach for fin stabilizer reinforced structural design and analysis. References | Related Articles | Metrics

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Design of a Parallel Double-Loop Control System for Air-Cushion Vehicles XU Shuo-1, LUO Zhe-2, YU Fan-2 2012, 46 (08):  1284-1290.  Abstract ( 2984 )   Save Linear/angular velocities and load distribution ratio could act as control variables for the propulsion system and the lifting system of an aircushion vehicle (ACV), respectively. They are independent in control and different in terms of control requirements and update frequencies for control objectives, but are both able to impact energy consumption. A parallel doubleloop control system cored with fuzzyPID controllers was designed to match these features, in which, velocity control tracks an instantaneous objective with a high update frequency, so that dynamic performance is paid more attention to; instead, load distribution radio control tracks a steadystate objective with a low update frequency and thus more importance is attached to static performance; besides, for the latter, the impact of slip ratio (a running variable relevant to velocities) is taken into account to reduce energy consumption, reflecting the idea of parameter coordinated control. The simulation results show that the ACV prototype can, under control, reach the destination with softlanding. The velocity control presents a good dynamic performance so as to benefit the vehicle’s safety, and the load distribution ratio control manifests a good static performance so as to decrease energy consumption. References | Related Articles | Metrics

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Study on Vehicle Chassis Integrated Control LI Gang-1, 2 , ZONG Chang-Fu-1, ZHANG Ze-Xing-1, DUAN Ming-Xu-1, LIANG He-Qi-3, HONG Wei-1 2012, 46 (08):  1291-1296.  Abstract ( 4482 )   Save For enhancing the vehicle stability in the extreme conditions, the vehicle horizontal integrated control of longitudinal and lateral movement ant the overall integrated control of longitudinal, lateral and vertical improvement were studied based on the model predictive control theory. The hierarchical integrated control structure was determined. The steering/braking model predictive controller and active suspension controller were disigned. The singlewheel braking force allocation method was used. It achieves the steering/braking horizontal integrated control  and the steering/braking/suspension overall integrated control. The simulation test was used to verify the algorithm. The result shows that the integrated control can enhance the vehicle stability and active safety effectively in the extreme conditions. References | Related Articles | Metrics

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Multi-objective Optimization of Hybrid Electrical Vehicle Based on Pareto Optimality YANG Guan-Ci-1, 2 , LI Shao-Bo-1, 2 , QU Jing-Lei-1, GUO Guan-Qi-3, ZHONG Yong-2 2012, 46 (08):  1297-1303.  Abstract ( 4591 )   Save Some basic theories about hybrid electric vehicle (HEV) were introduced. The multiobjective optimal model for minimizing the fuel consumption, the sum emission of HC and NOx, and the CO emission was established. A multiobjective evolutionary algorithm for hybrid electrical vehicle based on Pareto optimality (HEVMOEA) was proposed. HEVMOEA uses real coding method to represent gene, and employs ADVISOR to simulate HEV to obtain the value of each objective of candidate solutions, and adopts the Pareto dominance principle to evaluate each solution. A method was put forward to specify the significant digits of variables to guarantee the realizability. A series of simulation results show that HEVMOEA is capable of solving the multiobjective optimization design of HEV, and is promising to provide a set of alternative Pareto optimal solutions characterized with better fuel economy and emission performance for designer. References | Related Articles | Metrics

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Efficiency Analysis of Hybrid Energy Storage System  in Light Electric Vehicles WU Zhi-Wei, ZHANG Jian-Long, WU Hong-Jie, YIN Cheng-Liang 2012, 46 (08):  1304-1309.  Abstract ( 5577 )   Save The design of active parallel hybrid energy storage system (HESS) for light electric vehicles (LEVs) was presented by the use of high power density ultracapacitor and high energy density LiFePO4 battery. The battery efficiency was analyzed based on the experiment, and the theoretical efficiency of the bidirectional DC-DC power converter was derived. The combination of ultra-capacitor and LiFePO4 battery was discussed. The result demonstrates that the HESS with the bidirectional DC-DC power converter can improve the efficiency. The experimental result shows that the average efficiency of DC-DC is 90.5% in the HESS bench test, which is close to the theoretical efficiency 91.6%. References | Related Articles | Metrics

Aeronautics & Astronautics

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Simulation of Plume Impingement Effects in the Lunar Lander Environment YAN Li, WANG Ping-Yang, 欧Yang-Hua 2012, 46 (08):  1310-1314.  Abstract ( 3539 )   Save A calculation model of the interaction between rocket plume and moon surface was built using hybrid CFD/DSMC method. The correction of the model is achieved through comparing the results with other experimental data and simulation results. The comparison shows that the results are in good agreement and the model is credible. The plume of rocket coupled with moon surface and buffer structure was simulated, and the plume impingement effects on buffer structure and moon were analyzed. The results show that the maximum pressure is 110 Pa on buffer structure, and the maximum pressure on moon surface is 2 kPa. The force effect on buffer structure provides guides for design. Surface stress effect analysis is the foundation of lunar dust motion and pollution. References | Related Articles | Metrics

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Propulsive Performance Analysis of Tandem Wing Based on Sliding Mesh Method   YU Xian-Zhao-1, 2 , SU Yu-Min-1 2012, 46 (08):  1315-1319.  Abstract ( 3551 )   Save The propulsive performance of a tandem wing system that has a stationary trailing wing and a flapping leading wing was calculated. The viscous incompressible NavierStokes equations were solved by the finite volume method in conjunction with the Standard kε turbulence model. The sliding mesh method was adopted to achieve the relative motion between the leading wing and the trailing wing. The relationships between the reduced frequencies, flapping amplitude, and trailing distance with propulsive performance were investigated. The results show that the propulsive efficiency of tandem wing system is higher than single flapping wing in an appropriate reduced frequency and flapping amplitude region, and most of the thrust is produced by leading wing, the propulsive performance is minimal dependent on trailing distance. References | Related Articles | Metrics

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Numerical Investigation about Optimal Design of Open-Jet Rectangular Test Section in Low Speed Wind Tunnel CONG Cheng-Hua-a, b , REN Ze-Bin-b, PENG Qiang-a, b 2012, 46 (08):  1320-1327.  Abstract ( 2765 )   Save In order improve flow quality of the specific open-jet test section, the design technology of  a certain  low speed wind tunnel open-jet test section was studied using computational fluid dynamics (CFD). It presents the control equations and boundary conditions for numerical simulation. Then the details of numerical results about the different configurations were given. Comparing with full open-jet test section, the velocity uniformity of model region is evidently improved by use of collector. Honeycomb and screens have profound function on the velocity field such as uniformity, direction field and turbulence level. Further investigation on the size of test section and collector  indicates that the flow quality of model region is significantly improved when several measures are implemented such as extending the entrance length before test section, increasing the test section caliber and the changing location and size of the collector. Combination of satisfactory parameters, which can produce a more uniform velocity profile to arrive at the expected level, was obtained based on numerical results. References | Related Articles | Metrics

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Effect of Slat and Flap on Stall Characteristic of Civil Aircraft ZHOU Tao-1, LI Ya-Lin-1, LIANG Yi-Hua-2, CHEN Ying-Chun-1 2012, 46 (08):  1328-1333.  Abstract ( 3570 )   Save  To detect factors of affecting stall characteristic and stability of aircraft, slot parameter of outboard slat, separation face of inboard slat and fuselage, slot between slat and pylon, and slot parameter of flap were investigated. The results indicate that, root and tip of slat may affect pitching moment characteristic, slot between slat and pylon may improve lift coefficient, but no contribution for pitching moment characteristic, and, adjusting deploy angle of flap may not improve separation characteristic on main wing, because effective camber of wing is not changed. References | Related Articles | Metrics

Electrotechnology

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Scale Model Experimental Design on Lightning Shielding Performance of UHVDC Transmission Line JIANG An-Feng-1, LI Rui-Hai-2, WANG Guo-Li-2, FU Zheng-Cai-1 2012, 46 (08):  1334-1339.  Abstract ( 3151 )   Save Scale model experiment was used to revise the calculation method and the influence factors about lightning shielding performance of UHVDC transmission line were analyzed. According to the problems about scale model experiment, on-site observation and calculation method from domestic and oversea researchers, combining the test conditions of Kunming national engineering laboratory for UHV engineering technology, the existing experimental and observation results, this paper designed the key parameters, layout and experimental projects of typical air gap experiment, strike distance scale model experiment and upward leader scale model experiment of the ±800 kV UHVDC transmission line. References | Related Articles | Metrics

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A Simulation Analysis of Shanghai Pension Reform Based on System Dynamics WANG Yu-Xi-1, WANG Hong-1, 2 , CHEN Qun-Min-3, XIAO Jun-4 2012, 46 (08):  1340-1348.  Abstract ( 2663 )   Save By the use of census and 1% sampling investigation population data and yearbook data, combining the population actuarial science and system dynamics model with table function, six pension reform policy scenes are simulated. On the basis of pension gap forecast curve trend analysis, the new pension system merging policy may not only have a positive influence on Shanghai pension system in short term, but also have a negative influence on the persistence of pension in long term. Pension system may face a retire tide and a payment jump. 75% policy strength may be the best choice. The conclusion has important theoretical significance and applying value for the Shanghai pension reform policy research.  References | Related Articles | Metrics