水下无人系统学报

Study on Noise Generation Mechanism of Flow Interference for Torpedo Pump Jet Propulsor

ZHAO Bing, YIN Shao-ping, GAO Yong, CAI Wei-jun, GAO Zhi-yong

2009, 17(2): 001-4. doi: 10.11993/j.issn.1673-1948.2009.02.001

[Abstract](2211) [PDF 660KB](791)

Abstract:
To understand the flow noise generation mechanism of pump jet propulsor, this paper calculates the flow field of a torpedo pump jet propulsor,analyzes the field structure, and then calculates its broadband noise with Proudman theory. The result shows that the major noise source zone is in conformity with the character of the flow field, indicating the eddy pulse of the flow field is the main factor of noise.Moreover, an approach to control the flow noise of the pump jet propulsor is offered.

Numerical Analysis of Flow Noise for Underwater Vehicle

SONG Bao-wei, MA Ji, HU Hai-bao, LU Xiang, LIU Zhan-yi

2009, 17(2): 005-10. doi: 10.11993/j.issn.1673-1948.2009.02.002

[Abstract](2039) [PDF 532KB](795)

Abstract:
A turbulent boundary layer acoustic field of underwater vehicle is deduced with the large eddy simulation (LES) turbulent model and Lighthill′s acoustic analogy. The analysis shows that the transition zone of underwater vehicle has larger power spectral density than the development zone of underwater vehicle,the peak value of transition zone is in high frequency region, and the peak value of development zone is in low frequency region. The effect of velocity on spectrum of underwater vehicle is discussed. With velocity increasing the sound pressure of underwater vehicle rises, which causes the convective frequency moving back in the spectrum.

An Integrated Prediction Method of Torpedo Flow Noise

ZHAO Jia-peng, SHI Xiu-hua, DU Xiang-dang

2009, 17(2): 010-14. doi: 10.11993/j.issn.1673-1948.2009.02.003

[Abstract](1378) [PDF 469KB](560)

Abstract:
Based on boundary layer theory and radiated noise theory of boundary layer transition, the conventional torpedo flow noise prediction models are analyzed and compared, and an integrated prediction method of torpedo flow noise is hence presented. This new method improves the Liepmann analogy based on displacement thickness monopole sound source model by using Krane dipole sound source model, and considers the effects of pressure gradient and the loss of noise diffraction on boundary layer transition.Calculation results show that the transition in an adverse pressure gradient results in higher radiated noise in comparison with the transition in a zero pressure gradient, and the noise prediction by the integrated prediction method coincides with the measured one.

Stability Estimation for UUV with External Torpedoes

ZHOU Jie, WANG Shu-zong, ZHANG Zhi-xun

2009, 17(2): 015-19. doi: 10.11993/j.issn.1673-1948.2009.02.004

[Abstract](2016) [PDF 439KB](750)

Abstract:
To analyze the stability of unmanned underwater vehicle (UUV) with external torpedoes,this paper calculates the optimum location of external torpedoes, deduces a spatial motion model of the hung torpedoes, and then simplifies the model as longitudinal motion and transverse rolling. Disturbance equation is achieved, and the Laplace transform is performed by analyzing the reaction force imposed on UUV by the external torpedoes. The condition to estimate the stability of UUV with external torpedoes is finally obtained according to the stability criterion.

A Method to Improve AUV Navigation Accuracy Under Considerable Initial Alignment Errors

YAN Gong-min, YAN Wei-sheng, XU De-min

2009, 17(2): 020-24. doi: 10.11993/j.issn.1673-1948.2009.02.005

[Abstract](1988) [PDF 540KB](709)

Abstract:
For strapdown inertial navigation system (SINS) in autonomous underwater vehicle (AUV), launch shock or insufficient alignment time may result in considerable initial misalignment errors, and the azimuth misalignment error is a major factor to reduce AUV position accuracy. In this paper, dead-reckoning (DR) and strapdown gyro-compass alignment (GA) algorithms are synchronously executed soon after AUV launch using raw data from strapdown inertial measurement unit (SIMU) and Doppler velocity log (DVL). After a short-time of GA level tuning stage, DR level attitudes are corrected to diminish level errors, but DR azimuth is corrected only when GA is convergent during the azimuth adjustment stage. Azimuth error between GA and DR is calculated, and DR position errors can be estimated by the similarity theory of DR course and AUV actual course. Hence, AUV navigation accuracy can be improved. The simulation results show that the proposed method can perfectly correct position errors due to initial misalignment errors, but excluding position errors caused by DVL scale error. In the simulation case, AUV position errors diminish to 19.8% after error compensation.

A Wake Field Detection Mothod Using Laser Wavefront Variation

JI Bang-jie, WANG Hai-lu, YAN You-rong, LI Bi-li

2009, 17(2): 025-28. doi: 10.11993/j.issn.1673-1948.2009.02.006

[Abstract](1354) [PDF 429KB](670)

Abstract:
The physical characteristics of wake are very different from those of normal sea water, such as acoustic, optical, thermal and electromagnetic characteristics. So ship wake can be detected via its optical characteristic variation by laser. When laser propagates through ship wake, its wavefront varies, hence ship wake can be detected.Therefore, a wake field detection method using laser wavefront variation is presented in this paper. Experimental results show that the influence of micro-bubbles on wavefront variation is weak,but eddy flow imposes a significant effect on laser wavefront.This method may provide an approach to detect ship wake more effectively.

Space-Time Two-Dimensional Distribution of Reverberation in Shallow Water and Anti-Reverberation

ZHAN Hao-ke, CAI Zhi-ming, YUAN Bing-cheng

2009, 17(2): 029-32. doi: 10.11993/j.issn.1673-1948.2009.02.007

[Abstract](1695) [PDF 468KB](688)

Abstract:
Reverberation with different incident cone-angles, in shallow water spreads space-time coupling Doppler,and produces a certain bandwidth interference in frequency spectrum,which gives rise to great difficulty in detection of target. The Doppler bandwidth interference is found to have special two-dimensional space-time form in this paper. Consequently, the conventional method, which restrains reverberation using Doppler difference only in frequency spectrum,is not as satisfactory as the space-time method.Therefore,the application of space-time adaptive optimization method to active acoustic homing torpedo is studied, and the conventional method is improved by restraining the side lobe reverbereration and main lobe reverberation with self Doppler null method. Simulation results show that the two methods can both suppress the reverberation effectively, and the improved method can be implemented more easily in real-time process because of its less computation.

A Localization Algorithm with Combined Subsets for Multistatic Sonar System

SUN Yong, ZHAO Jun-wei, ZHANG Yin-bing, ZHANG Xiao-feng

2009, 17(2): 033-36. doi: 10.11993/j.issn.1673-1948.2009.02.008

[Abstract](1505) [PDF 387KB](650)

Abstract:
To improve the localization accuracy of bistatic sonar in such districts as baseline district, and side districts of transmitting and receiving stations, the most effective method is to increase the number of transmitting and receiving stations, which forms a multistatic sonar system. The mature algorithms for multistatic sonar system are the multistatic time-only localization (TOL) algorithm and the multistatic bearing-only localization (BOL) algorithm, which contain three measurements in one subset. This paper proposes a new algorithm by combining multistatic TOL algorithm and multistatic BOL algorithm for multistatic sonar system. The simulation results show that the proposed localization algorithm exhibits highest accuracy compared with the multistatic TOL algorithm, the multistatic BOL algorithm and the algorithm whose subset contains six measurements.

An Improved Vulcanization Technology for Torpedo Acoustic Array

LIU Jun-ka, GUO Tao, GONG Yuan

2009, 17(2): 037-39. doi: 10.11993/j.issn.1673-1948.2009.02.009

[Abstract](1458) [PDF 393KB](638)

Abstract:
To solve the problems in conventional vulcanization technology for torpedo acoustic array, a new scheme is presented, which takes selection of vulcanized materials, treatment of metal surface and distribution of elementary transduces into account.The experimental result and small batch production demonstrate that this scheme solves such problems as weak bonding of metal surface and rubber, and lower qualification rate of streamline control for sound transparent rubber,improves the qualification rate of acoustic array in manufacture, shortens the period of array production, and optimizes the acoustic performance of torpedo homing system, which all meet the need of mass production of torpedoes.

Simulation of Trajectory Logic for Wake Homing Torpedo

ZHAO Xiang-tao, SUN Xu-wen, ZHOU Ming

2009, 17(2): 040-44. doi: 10.11993/j.issn.1673-1948.2009.02.010

[Abstract](1894) [PDF 493KB](838)

Abstract:
According to the guidance characteristics of wake homing torpedo, the trajectory logic of wake homing torpedo is simulated using the object oriented programming method.A simulation model for wake of maneuvering surface vessel is established,the simulation principle of wake collision detection of homing torpedo is discussed,and the trajectory logic of wake homing torpedo is analyzed. Furthermore,a simulation method of trajectory of wake homing torpedo is presented, and a simulation of trajectory logic of wake homing torpedo is conducted. The analysis of the chart and data from the simulation demonstrates the correctness and feasibility of the simulation model.

Modeling of Underwater Turbine Engine Propulsion System

LUO Kai, SUN Jun-liang, DANG Jian-jun, WANG Yu-cai

2009, 17(2): 045-48. doi: 10.11993/j.issn.1673-1948.2009.02.011

[Abstract](1785) [PDF 475KB](708)

Abstract:
An underwater turbine engine propulsion system has the particularities of its structure characteristic and working condition.Mathematical modeling of the engine propulsion system is necessary for the system analysis and system design. Combining the physical mechanism analysis and characteristic data fitting of primary components,a mathematical model of propulsion system of underwater turbine engine system with open loop cycle is built in this paper.The model has simple structure,clear physical meaning and high calculating precision.And its parameters adjustment,program coding and calculation are convenient.The model can be used for performance evaluation and optimization design of the propulsion system.As the model describes the dynamic process of the system,it is the base of the design of the engine control system.

Thermal Analysis of Contrapositive Cam Engine Piston

YUAN Peng, GAO Sheng-yao

2009, 17(2): 049-52. doi: 10.11993/j.issn.1673-1948.2009.02.012

[Abstract](1971) [PDF 455KB](706)

Abstract:
Studying thermal load of the piston of a contrapositive cam engine may provide theory for strength analysis and strucure optimization in engine development and innovation. By using finite element method (FEM) we establish a thermal model,define the boundary condition and simulate the temperature field of the piston. The results show that the temperature of whole piston is overheated,so structural parameter optimization of the piston is necessary to enhance its wearing resistance.

Simulation of Measuring Torpedo Launch Noise in Submarine Based on Towed Array Sonar

CHENG Guang-tao, ZHANG Zhen-Shan, ZENG Guang-hui

2009, 17(2): 053-56. doi: 10.11993/j.issn.1673-1948.2009.02.013

[Abstract](1813) [PDF 535KB](649)

Abstract:
Based on the exercitation theory of‘launching water’,a simulation of measuring torpedo launch noise by using submarine′s towed hydrophone array was conducted through constant radius turn manoeuvre of submarine. Position parameters were obtained from the simulation with the model of towed array.Based on the theory of radiated noise forming, the launch noise was simulated according to test condition in Laboratory,and the result showed the launch impulsion noise obeyed SαS distribution. The simulated noise attenuating in deep sea was analyzed with a sound loss translation model.Minimum variance distortionless response(MVDR),spatially smoothed MVDR, and beam-space multiple signal classification (BMUSIC) algorithm were adopted to process the signal, hence the source level, the frequency structure and the location of the launch noise were achieved.Simulation results show that the test scheme is feasible,and launch noise data can be obtained for the research of vibration suppression and noise reduction in torpedo launcher.

Study on Fire Efficiency of Rocket-Assisted Torpedo Based on Over-the-Horizon Fire Channel

KOU Zhu, ZHOU Ming

2009, 17(2): 057-60. doi: 10.11993/j.issn.1673-1948.2009.02.014

[Abstract](1653) [PDF 453KB](736)

Abstract:
When rocket-assisted torpedo is adopted to attack submarine,the over-the-horizon fire channel taking helicopter-dipped sonar as information instructing resource can take advantages of long range and high speed of rocket-assisted torpedo completely.The precision of target motion factor and the channel reaction time determined by the fire channel have significant influence on fire channal performance.In this paper,the precision of target motion factor and the channel reaction time are analyzed, and the formulas are deduced.Simulation is performed with Monte-Carlo method to analyze their effects on fire efficiency of rocket-assisted torpedo.Moreover,some methods for improving the precision of target motion factor and the channel reaction time are suggested.

Virtual Training System for Torpedo Test Based on Visual j⁺⁺

LI Wei, LIU Hai-guang, WANG Gui-qin

2009, 17(2): 061-64. doi: 10.11993/j.issn.1673-1948.2009.02.015

[Abstract](1185) [PDF 588KB](651)

Abstract:
To meet the practical operation and training requirements for torpedo test,an idea of substituting microcomputer simulating operation on virtual panel for practical operation training is presented, a virtual training system of torpedo is therefore developed.The function design and implementing methods,especially the program design method based on Visual j++,are proposed.The e-book multimedia learning function, equipment simulation training function, and operation examination-microcomputer judging function are combined to realize the network virtual training system oriented to torpedo technological preparation process.

2009 Vol. 17, No. 2

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