舰艇编队通信对抗分析

针对目前我舰艇编队海上通信主要依靠短波和超短波通信的现状 ,从侦察、干扰两个方面 ,探讨了通信对抗分析的一般方法     

变结构控制在船舶操纵中的应用

本文根据船舶操纵系统的具体特点，为限制水域中的船舶操纵提供了一种变结构控制方案，同时考虑了航向纠编和航迹调整。根据一种特定航道设计的变结构控制系统可适用于一定范围内的其他航道内的船舶操纵，且控制精度高，无抖振发生。     

热分层环境下船模尾流温度分布与扩展规律的试验研究

通过对船模在水槽中稳定热分层环境下运动后留下的尾流中的温度测量及红外摄像，试验研究了双螺旋桨船模在二种速度运动下，螺旋桨相对向内旋转、向外旋转及螺旋桨不工作时，船模尾流中的温度分布与与扩展规律。     

SECOND-ORDER MOMENT TWO-PHASE TURBULENCE MODEL ACCOUNTING FOR TURBULENCE MODULATION IN SWIRLING SUDDEN-EXPANSION CHAMBER

A semi-empirical turbulence enhancement model accounting for the particle-wake effect was incorporated into the second-order moment two-phase turbulence model and employed to simulate gas-particle flows in a swirling sudden-expansion chamber. The simulated results for two-phases mean velocities and fluctuation velocities coincide well with the experiment ones, which demonstrates that this model, in comparison with the turbulence model not accounting for the wake effect, leads to higher calculating accuracy.     

水利枢纽船闸引航道口门区流态改善措施

阐述了水利枢纽船闸引航道口门区各种不利流态产生的原因，及其危害性，和提出了改善的措施。并结合工程实例说明这些改善措施的效果。     

The impact of yaw error on aeroelastic characteristics of a horizontal axis wind turbine blade

Horizontal axis wind turbines operate under yawed conditions for a considerable period of time due to the power control mechanism or sudden changes in the wind direction. This in turn can alter the dynamic characteristics of a turbine blade because the flow over the rotor plane may trigger complicated induced velocity patterns. In this study, an aeroelastic analysis under yawed flow conditions is carried out to investigate the effects of yaw error on the blade behaviors and dynamic stability. A beam model including geometric nonlinearity coupled with unsteady aerodynamics based on a free-vortex wake method with the blade element theory is employed in the present study. The aerodynamic approach for a horizontal axis wind turbine blade under yawed flow conditions is verified through comparison with measurements. It is also shown that the present method gives slightly better results at high yaw angles than does the method previously published in the literature. The dynamic instabilities of a National Renewable Energy Laboratory 5 MW reference wind turbine have subsequently been investigated for various wind speeds and yaw angles. Observations are made that yaw effects induce considerable changes in airloads and blade structural behavior. Also, the aeroelastic damping values for this particular blade under yawed flow conditions can be reduced by up to approximately 33% in the worst case. Therefore, it is concluded that the impacts of yaw misalignments adversely influenced the dynamic aeroelastic stability of the horizontal axis wind turbine blade.     

THE EFFECT OF WAVE GROUPINESS ON A MOORED SHIP STUDIED BY NUMERICAL SIMULATIONS

Waves with the same wave parameters, such as significant wave height and period, but with different wave groupiness factors are simulated, to study the motion behavior of a moored ship under the action of waves with different Groupiness Factors of Height (GFH) and Group Length Factors (GLF). The numerical results show that both the sway and heave motions increase with an increase in GFH. In contrast, the influence of GLF on the motions of a moored ship is weak.     

IDENTIFICATION OF ABKOWITZ MODEL FOR SHIP MANOEUVRING MOTION USING e-SUPPORT VECTOR REGRESSION

By analyzing the data of longitudinal speed,transverse speed and rudder angle etc.in the simulated 10o/10o zigzag test,the hydrodynamic derivatives in the Abkowitz model for ship manoeuvring motion are identified by using ε-Support Vector Regression(ε-SVR) .To damp the extent of parameter drift,a series of random numbers are added into the training samples to reconstruct the training samples.The identification results of the hydrodynamic derivatives are compared with the Planar Motion Mechanism(PMM) test results to verify the identification method.By using the identified Abkowitz model,20o/20o zigzag test is numerically simulated.The simulated results are compared with those obtained by using the Abkowitz model where the hydrodynamic derivatives are obtained from PMM tests.The agreement is satisfactory,which shows that the regressive Abkowitz model has a good generalization performance.     

基于MSC Dytran的潜艇结构撞击强度分析

提出潜艇碰撞问题,对其碰撞特征进行分析,并针对某型潜艇舯部典型结构的撞击极限强度特性进行数值计算,结果表明由于准静压载荷的附连耦合作用,随着静水压力的增加,潜艇舯部耐压壳体结构的防撞能力大幅下降,而耐压壳体内部的平台和舱壁结构能有效提高壳体结构的横向失稳临界应力,改善潜艇结构的径向耐撞能力.     

Deep- and shallow-water slamming at small and zero deadrise angles

This paper reviews and extends theories for two classes of slamming flows resulting from the violent impact of bodies on half-spaces of inviscid fluid. The two configurations described are the impact of smooth convex bodies, and of non-smooth but flat-bottomed bodies, respectively. In each case, theories are presented first for small penetration depths in finite- or infinite-depth fluids (which we call Wagner flows), and secondly when the penetration is comparable to the fluid depth (which we call Korobkin flows). We also discuss the transition from Wagner flow to Korobkin flow.