• 中国科技核心期刊
  • JST收录期刊

2015 Vol. 23, No. 4

Display Method:
Discussion on Tactics, Techniques, and Procedures
QIAN Dong, ZHAO Jiang
2015, 23(4): 241-256. doi: 10.11993/j.issn.1673-1948.2015.04.001
Abstract:
The concept and significance of tactics, techniques, and procedures (TTPs) are described from the aspects of tactical countermeasures and new equipment. Some key points of American army's TTPs are cited. Some classic examples of innovation on methods of operation by Chinese surface-to-air missile troops are introduced. Some methods and factors of air-to-ground attack by American air force are analyzed, including operational environment, target characteristics, mission planning, searching and tracking, operational coordination, weapon application and attack strategy, precise strike and damage control, tactics and techniques, cooperative engagement, etc. And the enlightenment on undersea warfare is discussed as well. It point out that TTPs are the methods and guidelines for effective organization and integrated application of operational resources, the bridge between operation and armament, and the linkage between tactics and techniques. They are very important for future weapon development and unmanned operations. The study of TTPs should be oriented to weapon application, pay attention to principle of development, and lay emphasis on basic research. It is necessary to understand modern operation rules at system level.
Failure Mode of Torpedo Nose Cap in Water-entry
QIAN Li-xin, LIU Fei, QU Ming, HU Yan-hui, ZHAO Jian-bo
2015, 23(4): 257-261. doi: 10.11993/j.issn.1673-1948.2015.04.002
Abstract:
The failure process and leading influencing factors of a torpedo nose cap in water-entry are analyzed to reveal failure mechanism and study theoretical design method of the nose cap. The dynamics of water-entry is numerically simulated and verification test is conducted for the nose cap with given boundary conditions. The test result shows that the mode of “wedging-in failure” is the effective failure mode of the nose cap in water-entry. The strength matching design between the top portion and the weak-links of pre-formed groove is a necessary condition for the nose cap to implement this failure mode. The concept of feasible region of the nose cap is proposed based on the wedging-in failure mode as the physical boundary of structural design of a torpedo nose cap.
Calculation of Hydrodynamic Characteristics of Supercavity Vehicle with CFD Method
LI Yu-tian
2015, 23(4): 262-268. doi: 10.11993/j.issn.1673-1948.2015.04.003
Abstract:
In the mode of supercavitation, the flow field of an underwater vehicle involves three types of media—— solid, liquid and gas, and the inter-coupling effect of cavity and vehicle is extremely complicated. In this paper, four typical characteristics of fluid dynamics of a supercavity vehicle, i.e. resistance reduction characteristic, nonlinear, unsteady and uncertain, and smaller fluid inertia force, are summarized, and the nature of fluid dynamics for an underwater vehicle in supercavitation is revealed. The cavity shapes are simulated with the changes of cavitation number, angle of attack, and angle of rudder. The method of computational fluid dynamics(CFD) is used to calculate the forces on a supercavity vehicle with given shape under different conditions. The changes of hydrodynamic characteristics of the vehicle, as well as the relevant influencing factors, are analyzed.
Receive-Transmit Coupling Interference Suppression for Torpedo Electro-magnetic Fuze Target Simulation System Based on Adaptive Cancellation
YAN Zheng-tong, XIAO Su-juan, BAI Zhi-ke, CHEN Ya-lin
2015, 23(4): 269-275. doi: 10.11993/j.issn.1673-1948.2015.04.004
Abstract:
Considering the importance of receive-transmit coupling interference suppression problem in simultaneous transmit-receive operation for the target echo simulation system, a coupling model of torpedo electromagnetic fuze for target echo simulation system is established in the condition of simultaneous transmit-receive operation. An adaptive cancellation algorithm is proposed to achieve real-time separation of target signal and coupling interference. The model and algorithm are analyzed via simulation and calculation, laying emphasis on the influence of parameters selection for the adaptive cancellation algorithm on the performance of coupling interference suppression. Simulation results show that the coupling interference suppression could be solved by the proposed algorithm if the parameters are selected properly. With respect to real-time property and stability of adaptive cancellation, the recursive least squares algorithm behaves better than the least mean square algorithm.
An Algorithm of Target Detection in Bubbly Water
WU Shuang, YANG Chang-sheng, LIANG Hong
2015, 23(4): 276-279. doi: 10.11993/j.issn.1673-1948.2015.04.005
Abstract:
It is quite difficult to detect targets using man-made sonar due to the existance of bubbles, while researches indicate that dolphins outperform man-made sonar in detecting targets in bubbly water. The signals emitted by dolphins are in the form of pulse sequences, and some of two adjacent pulses are of inverted phase. In this study, the bubble model of Keller-Miksis equation and the twin inverted pulse sonar(TWIPS) are used to investigate the effectiveness of target detection of the dolphin-like clicking sound pulse pair with inverted phase in bubbly water. Furthermore, the performances are compared between TWIPS and standard sonar. Simulation results show that for the detection of linear target, TWIPS behaves better than the standard sonar in given bubble cloud distribution.
Imaging of Multi-receiver SAS with Faulty Array Element
ZHANG Yuan-biao, ZHU San-wen
2015, 23(4): 280-284. doi: 10.11993/j.issn.1673-1948.2015.04.006
Abstract:
One or several array element in array receivers may lose efficacy due to unpredictable factors during testing process, and hence seriously affect performance of whole synthetic aperture sonar (SAS) system. This paper proposes an imaging method of multi-receiver SAS with faulty array element to resolve the image distortion caused by the invalid receivers. In this method, the signal from the invalid array element is reconstructed based on linear prediction, then synthetic aperture imaging processing is performed. Simulation results show the validity and feasibility of the proposed method.
Pulse Trains of Linear Frequency-modulated Signal and Its Detection Performance
YUE Lei
2015, 23(4): 285-290. doi: 10.11993/j.issn.1673-1948.2015.04.007
Abstract:
For active sonar reverberation suppression, the characteristics of pulse trains of linear frequency-modulated (PTLFM)signal is studied in terms of time domain, frequency domain, and ambiguity function, and the wideband symmetrical triangular frequency-modulated PTLFM signal is adopted to improve the reverberation suppression performance on speed sidelobe. PTLFM waveform design is completed following the comb spectrum signal design requirements, and detection of target with different velocity is performed by making use of measured data of PTLFM signal with complicated background. Theoretical analysis, simulation results and measured data show that the reverberation suppression performance of the sawtooth PTLFM signal is better than that of the symmetrical triangular PTLFM signal for static or moving target, while the reverberation suppression performance of the symmetrical triangular PTLFM signal is better for the target whose velocity is the maximum speed sidelobe of its ambiguity function. This study may provide a reference for anti-reverberation waveform design.
One-Dimensional Modelling and Simulation of Torpedo Shell Condenser in Closed-loop Thermal Propulsion System
HAN Yong-jun, YANG Cheng-shi, PENG Bo, GUO Zhao-yuan, LU Jun, MA Wei-feng
2015, 23(4): 291-295. doi: 10.11993/j.issn.1673-1948.2015.04.008
Abstract:
To understand heat transfer characteristic in shell condenser of closed-loop thermal propulsion system of a torpedo, a one-dimensional heat exchange model of the shell condenser is built. And the temperature, pressure and dryness distributions along the axis of the shell condenser are acquired with the model. In addition, the influences of three factors on the performance of the shell condenser are discussed. These factors are the cross-section size of cooling channel, the mass flow rate and the temperature of inlet steam exhaust. Simulation results indicate that, for same condenser inlet steam exhaust, heat exchange of the cooling channel is affected by its cross-section area. The outlet temperature of the condenser significantly depends on the inlet steam exhaust temperature, and the outlet pressure mainly depends on the mass flow rate of inlet steam exhaust. This study may provide a reference for performance prediction and structure design of torpedo shell condensers.
New Design Approach of Scarfed Nozzle in Underwater Impulse Turbine
JIANG Bin, LUO Kai, GAO Ai-jun, FENG Qi-xi, YI Jin-bao
2015, 23(4): 296-300. doi: 10.11993/j.issn.1673-1948.2015.04.009
Abstract:
Considering the inner flow loss of nozzles, the deflection of the outlet flow, the pressure loss and leaving- velocity loss of turbine cascades, a new design approach of the scarfed nozzle is presented for an underwater partial air inlet impulse turbine to modify the conventional design approach. The feasibility of the present approach is verified by numerical simulations. Compared with the conventional design approach, the inner efficiency of the modified turbine is raised by about 5%, and the outlet static pressure is closer to the designed back pressure. The present design approach may provide a reference for the design of turbine′s scarfed nozzles.
Modeling and Simulation of Flow and Heat Transfer of Working Medium in Spiral Tube Evaporator
BAI Jie, DANG Jian-jun, LI Dai-jin, WANG Xiao-xin
2015, 23(4): 301-304. doi: 10.11993/j.issn.1673-1948.2015.04.010
Abstract:
A steady state one-dimensional distributed parameter model of the spiral tube evaporator is built to study its property in the combustion reactor for an underwater vehicle. The evaporator is divided into many units along the tube to obtain the state parameters of the working medium along flow direction by the calculation of each unit. The flow and heat transfer processes during the working medium is heated to superheated steam are analyzed via simulation. The changes of the temperature and pressure in the tube are compared for different flow rate and temperature of the inlet working medium. Simulation results show that: the pressure loss during the medium passing through evaporator occurs mostly in two-phase area and vapor area, but the loss is small compared with the pressure of the medium itself; higher inlet temperature of the working medium improves the heat exchange performance and raise outlet vapor temperature; and reducing inlet flow rate significantly results in higher outlet vapor temperature. The proposed model may be applicable to spiral tube design and thermal calculation of power system for underwater vehicles.
Multi-model Adaptive Federated Kalman Filter and Its Application to Torpedo Navigation and Positioning
CAO Meng, LI Jian-chen, GUO Lin-na, HUANG Hai, HONG Jian-ying
2015, 23(4): 305-310. doi: 10.11993/j.issn.1673-1948.2015.04.011
Abstract:
Aiming at the problem that traditional fixed parameter filter lose its precision due to parameter variation of torpedo integrated navigation system model in complicated environment, a multi-model adaptive federated Kalman filter is designed for a torpedo integrated navigation system. The Kalman filter adopts multi-model adaptive federated filtering algorithm, which can approximate the dynamic performance of the system by making use of multi-model filter parameters. Furthermore, an adaptive information distribution strategy for information fusion is employed in the federated filter. The results of navigation test in laboratory show that the multi-model adaptive federated Kalman filter can improve estimation precision, tracking speed and stability of the navigation system greatly.
Simulation of Point Target Echo Based on the Actual Hydrological Conditions
CHEN Fa, LI Yong-sheng, ZHAO Gang, LÜ Lin-xia, CHEN Ya-lin
2015, 23(4): 311-315. doi: 10.11993/j.issn.1673-1948.2015.04.012
Abstract:
To analyze the influences of hydrological conditions on the signal of an active hydroacoustic detection system, the ray acoustic theory and BELLHOP models are employed to solve the eigenray from measured oceanic hydrological data. A point target echo model is built with the information of amplitude, time-delay, and phase, which are carried by the main eigenray. The point target echo waveform is obtained from numerical simulation in the case of transmitting single-frequency sine impulse, and is compared with the measured waveform. Computational results show that the point target echo model based on hydrological conditions is applicable to simulate the influences of hydrological conditions on underwater sound signal.
A Fast Simulation Method for Nonlinear Ocean Wave
WANG Lan, ZHOU Lin-yi, NIE Wei-dong
2015, 23(4): 316-320. doi: 10.11993/j.issn.1673-1948.2015.04.013
Abstract:
Great emphases have been put on simulation of nonlinear ocean wave in some navy projects. This paper presents a fast method for simulating nonlinear ocean wave in deep sea. The basic idea of this method is to nonlinearly correct the linear simulation data according to the statistic characteristics of nonlinear ocean wave. First, a white noise is filtered by JONSWAP filter to obtain linear result. Then, the linear result is corrected to nonlinear one based on B-distribution characteristics to simulate the blue water two-dimensional unbroken wave. The wave data computed by this method shows the non-normality of real ocean wave. The power spectrum estimated from the nonlinear result is fairly close to JOSWAP spectrum, which indicates that the simulated wave energy distribution accords with the real wave data.
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