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3D numerical simulation on fluid-structure interaction of structure subjected to underwater explosion with cavitation

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Applied Mathematics and Mechanics(English Edition) 2012年第9期33卷 1191-1206页

作者：张阿漫任少飞李青李佳 College of shipbuilding Engineering Harbin Engineering University china ship development and design center

In the underwater-shock environment, cavitation occurs near the structural surface. The dynamic response of fluid-structure interactions is influenced seriously by the cavitation effects. It is also the difficulty in the field of underwater explosion. With the traditional boundary element method and the finite element method （FEM）, it is difficult to solve the nonlinear problem with cavitation effects subjected to the underwater explosion. To solve this problem, under the consideration of the cavitation effects and fluid compressibility, with fluid viscidity being neglected, a 3D numerical model of transient nonlinear fluid-structure interaction subjected to the underwater explosion is built. The fluid spectral element method （SEM） and the FEM are adopted to solve this model. After comparison with the FEM, it is shown that the SEM is more precise than the FEM, and the SEM results are in good coincidence with benchmark results and experiment results. Based on this, combined with ABAQUS, the transient fluid-structure interaction mechanism of the 3D submerged spherical shell and ship stiffened plates subjected to the underwater explosion is discussed, and the cavitation region and its influence on the structural dynamic responses are presented. The paper aims at providing references for relevant research on transient fluid-structure interaction of ship structures subjected to the underwater explosion.

关键词： underwater explosion spectral element method (SEM) fluid-structure interaction cavitation stiffened plate

Coupled Heat and Mass Transfer Analysis of NH3-H2O Falling Film Absorption on Inner Tube Surface with Low Solution Flow Rates

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Journal of shanghai Jiaotong university(Science) 2016年第4期21卷 395-405页

作者：林芃王如竹 china ship development and design center Shanghai 201108 China Institute of Refrigeration and Cryogenics Shanghai Jiaotong University Shanghai 200240 China

NH_3-H_2O falling film absorption usually takes place with low solution flow rate in real absorption refrigeration system. An experimental study of inner vertical absorption is carried out for the consideration of air-cooling absorber. Variable working conditions are tested to evaluate the heat and mass transfer *** traditional evaluation method based on log-mean-temperature(concentration) difference is criticized for its lack of theoretical basis while simultaneous heat and mass transfer process occurs. A new method proposed by Kim and Infante Ferreira is modified to evaluate the experimental results with reasonable assumptions. The method is based on the derivation of coupled heat and mass transfer differential equations of NH_3-H_2O absorption *** analysis of the same experimental data shows that the new method realizes better consistency with smaller error, especially in heat transfer aspect. Heat and mass transfer performance is enhanced with the increase of solution Reynolds number. Sub-cooling of inlet weak solution also has positive influence on the absorption process,which should be evaluated by the new method correctly. Two correlations are developed to evaluate both Nusselt and Sherwood numbers for the design of air-cooling absorber.

关键词： falling film absorption heat and mass transfer ammonia-water

Sliding mode control design for oblique wing aircraft in wing skewing process

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Chinese Journal of Aeronautics 2019年第2期32卷 263-271页

作者： Ting YUE Zijian XU Lixin WANG Tong WANG School of Aeronautic Science and Engineering Beihang University china ship development and design center

When the wing of Oblique Wing Aircraft(OWA) is skewed, the center of gravity, inertia and aerodynamic characteristics of the aircraft all significantly change, causing an undesirable flight dynamic response, affecting the flying qualities, and even endangering the flight safety. In this study,the dynamic response of an OWA in the wing skewing process is simulated, showing that the threeaxis movements of the OWA are highly coupled and present nonlinear characteristics during the wing skewing. As the roll control efficiency of the aileron decreases due to the shortened control arm in an oblique configuration, the all-moving horizontal tail is used for additional roll and the control allocation is performed based on minimum control energy. Given the properties of pitchroll-yaw coupling and control input and state coupling, and the difficulty of establishing an accurate aerodynamic model in the wing skewing process due to unsteady aerodynamic force, a multi-loop sliding mode controller is formulated by the time-scale separation method. The closed-loop simulation results show that the asymmetric aerodynamics can be balanced and that the velocity and altitude of the aircraft maintain stable, which means that a smooth transition is obtained during the OWA's wing skewing.

关键词： Decoupling Dynamic response Oblique wing aircraft Sliding mode control Wing skewing process

Experimental Study and System Identification of Hydrodynamic Force Acting on Heave Damping Plate

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china Ocean Engineering 2008年第1期22卷 141-149页

作者：纪亨腾范菊黄祥鹿 china ship development and design center (shanghai Division) School of Naval Architect Ocean and Civil Engineering Shanghai Jiao Tong University

Although Morison equation is often applied for simulating hydrodynamic force of marine structure, it may give poor results when non-linear behavior is severe or random wave is encountered. This leads to some modifications of Morison equation or other methods for predicting hydrodynamic force. One of them is the system identification technique. In this paper, NARMAX model theory is firstly used to identify the hydrodynamic system of heave damping plates, which are commonly installed on spar platform. Both linear and non-linear models are obtained. The comparisons between the predieted results and measured data indicate that NARMAX model can predict hydrodynamic force of a heave damping plate very well. The measured data for identification originate from forced oscillation tests, which are random records with given spectrum. The forced oscillation forms in experiment also contain simple harmonic, multi-frequency ones.

关键词： heave damping plate Morison equation system identification NARMAX model

A New Delaunay Triangulation Algorithm Based on Constrained Maximum Circumscribed Circle

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Wuhan University Journal of Natural Sciences 2015年第4期20卷 313-317页

作者： CAO Ming china ship development and design center

Delaunay triangulation is gradually playing an important role in the field of finite element analysis, image recognition, and medical *** the quality and partition efficiency, a new Delaunay triangulation method based on constrained maximum circumscribed circle is proposed. First, according to two important criteria, the empty circle features and the maximized minimum angle characteristics, we established constrained conditions. Then, we iterated the container vertices, structure triangular face linked lists, and finally got the Delaunay data. The experimental results showed that the efficiency of the improved triangulation dissection method increased by 9.47% compared with traditional triangulation algorithms in irregular triangle vertex data.

关键词： constrained maximum circumcircle empty circle features maximize minimum angle characteristics

Broadband low-frequency sound absorption of multifunctional composite metastructure

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Science china Technological Sciences 2025年

作者： Yilong YANG Shanshan LIU Yan LI Tong GAO Yongdong PAN Yong LI Yabin JIN School of Aerospace Engineering and Applied Mechanics Tongji University Institute of Acoustics School of Physics Science and Engineering Tongji University shanghai Institute of Aircraft Mechanics and Control State International Joint Research center of Aerospace design and Additive Manufacturing Northwestern Polytechnical University shanghai Key Laboratory of Intelligent Sensing and Detection Technology School of Mechanical and Power Engineering East China University of Science and Technology

In this study, we fabricated multifunctional metastructures from carbon fiber-reinforced plastic composites using additive manufacturing technology. These metastructures are characterized by their lightweight, load-bearing capacity, and broadband low-frequency sound absorption properties. The metastructure consists of 36 unit cells, and non-local coupling mechanism was considered for designing the sound absorption performance. We developed an acoustic impedance theory tailored for the metastructure, facilitating an analysis of thermal and viscous dissipation mechanisms. It is proven theoretically and experimentally that the proposed composite metastructure can achieve a noise reduction with an average sound absorption coefficient greater than 0.9 across frequencies in the rage of 330–1500 Hz. We also studied the metastructure’s quasi-static and cyclic compression performance, confirming its efficient absorption capabilities after cyclic compression. The proposed design and additive manufacturing method for composite metastructures provides a novel pathway for creating lightweight, multifunctional structures with diverse applications, such as aerospace engineering.

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Characteristics of the Internal Waves Generated by a Towed Model with Rotating Propeller Under a Strong Halocline

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Journal of shanghai Jiaotong university(Science) 2019年第2期24卷 176-183页

作者： DUAN Ningyuan CHEN Ke WANG Hongwei YOU Yunxiang State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University china ship development and design center (shanghai)

Experiments are performed on the internal waves(IWs) generated by a towed model with rotating propeller in a density-stratified fluid with linear halocline; the Reynolds number ranges from 7 000 to 84 000, and the Froude number ranges from 0.7 to 8.1. The wave speed, amplitude and patterns are investigated on the basis of the multi-channel conductivity probe array technology and the cross correlation analysis method. It is shown that the propeller advances the transition from the body-generated IWs to the wake-generated IWs. Before the transition, the IWs are stationary to the translational model. An extra V-shaped wave with a narrow opening angle is generated by the propeller and the wave amplitude becomes larger with the increase of the thrust momentum,indicating that the propeller produces body and wake effects at the same time before the transition. After the transition, the Froude number associated with the wave speed drops down and fluctuates within 0.4—1.5, showing that the IWs are nonstationary to the model. The interaction of the drag momentum and the thrust momentum changes the characteristics of the wave amplitudes and patterns. The wave amplitude no longer simply grows with the Froude number but depends on the contrast of the drag momentum and the thrust momentum. Experimental results show that the most obvious contrast of the wave pattern contour maps appears when the drag momentum and the thrust momentum have the largest difference if other conditions are the same. When the ratio of the drag momentum to the thrust momentum is within 1—10, the wake can be considered as zero-momentum, meaning that the momentum difference is not enough to generate large scale structures in the wake.

关键词： internal wave(IW) stratified fluid momentum wake self-propelled model

Real-time Energy Management of Low-carbon ship Microgrid Based on Data-driven Stochastic Model Predictive Control

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CSEE Journal of Power and Energy Systems 2023年第4期9卷 1482-1492页

作者： Hui Hou Ming Gan Xixiu Wu Kun Xie Zeyang Fan Changjun Xie Ying Shi Liang Huang the School of Automation Wuhan University of TechnologyWuhan 430070China the Shenzhen Research Institute Wuhan University of TechnologyShenzhen 518000China china ship development and design center Wuhan 430064China. Key Laboratory of Marine Intelligent Equipment and System Shanghai Jiao Tong UniversityShanghai 200240China the china ship development and design center Wuhan 430064China.

With increasing restrictions on ship carbon emis-sions,it has become a trend for ships to use zero-carbon energy such as solar to replace traditional fossil ***,uncer-tainties of solar energy and load affect safe and stable operation of the ship *** order to deal with uncertainties and real-time requirements and promote application of ship zero-carbon energy,we propose a real-time energy management strategy based on data-driven stochastic model predictive ***,we establish a ship photovoltaic and load scenario set consid-ering time-sequential correlation of prediction error through three *** steps include probability prediction,equal probability inverse transformation scenario set generation,and simultaneous backward method scenario set ***,combined with scenario prediction information and rolling op-timization feedback correction,we propose a stochastic model predictive control energy management *** each scenario,the proposed strategy has the lowest expected operational cost of control ***,we train the random forest machine learn-ing regression algorithm to carry out multivariable regression on samples generated by running the stochastic model predictive ***,a low-carbon ship microgrid with photovoltaic is *** results demonstrate the proposed strategy can achieve both real-time application of the strategy,as well as operational cost and carbon emission optimization performance close to stochastic model predictive *** Terms-Data-driven stochastic model predictive control,low-carbon ship microgrid,machine learning,real-time energy management,time-sequential correlation.

关键词： Data-driven stochastic model predictive control low-carbon ship microgrid machine learning real-time energy management time-sequential correlation.

Underwater Terrain Positioning Method Based on Least Squares Estimation for AUV

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china Ocean Engineering 2015年第6期29卷 859-874页

作者：陈鹏云李晔苏玉民陈小龙姜言清 Science and Technology on Underwater Vehicle Laboratory Harbin Engineering University china ship development and design center

To achieve accurate positioning of autonomous underwater vehicles, an appropriate underwater terrain database storage format for underwater terrain-matching positioning is established using multi-beam data as underwater terrainmatching data. An underwater terrain interpolation error compensation method based on fractional Brownian motion is proposed for defects of normal terrain interpolation, and an underwater terrain-matching positioning method based on least squares estimation（LSE） is proposed for correlation analysis of topographic features. The Fisher method is introduced as a secondary criterion for pseudo localization appearing in a topographic features flat area, effectively reducing the impact of pseudo positioning points on matching accuracy and improving the positioning accuracy of terrain flat areas. Simulation experiments based on electronic chart and multi-beam sea trial data show that drift errors of an inertial navigation system can be corrected effectively using the proposed method. The positioning accuracy and practicality are high, satisfying the requirement of underwater accurate positioning.

关键词： multi-beam sounding data underwater digital terrain map fractional Brownian motion least squaresestimation terrain matching positioning fisher diseriminant