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Numerical and Experimental Study of Blockage Effect Correction Method in Towing Tank

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China Ocean Engineering 2019年第5期33卷 522-536页

作者： guo chun-yu XU Pei WANG Chao KAN Zi College of Shipbuilding Engineering Harbin Engineering University Harbin 150001 China Scool of Aeronautic Science and Engineering Beihang University Beijing 100191 China

When a ship model test is performed in a tank, particularly when the tank is small and the ship model is relatively large, the blockage effect will inevitably occur. With increased ship model scale and speed, the blockage effect becomes more obvious and must be corrected. In this study, the KRISO 3600 TEU Container Ship (KCS) is taken as a model and computational fluid dynamics techniques and ship resistance tests are applied to explore the mechanism and correction method of the blockage effect. By considering the degrees of freedom of the sinkage and trim, the resistance of the ship model is calculated in the infinite domain and for blockage ratios of 1.5%, 1.8%, 2.2%, and 3.0%. Through analysis of the free surface, pressure distribution, and flow field around the ship model, the action law of the blockage effect is studied. The Scott formula and mean flow correction formula based on the average cross sectional area are recommended as the main correction methods, and these formulas are improved using a factor for the return flow velocity correction based on comparison of the modified results given by different formulas. This modification method is verified by resistance test data obtained from three ship models with different scale ratios.

关键词： blockage effect ship model resistance blockage ratio KCS ship CFD

Online social network model with renewal and accelerated growth

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The Journal of China Universities of Posts and Telecommunications 2014年第4期21卷 54-63页

作者： WU Zhe guo yu-chun CHEN Chang-jia School of Electrical and Computer Engineering Beijing Jiaotong University

Based on observation of the growing mechanism in Twitter-like online social networks, an online social network （OSN） evolution model was proposed, a renewal mechanism for the old nodes and an accelerated growth mechanism was introduced for the new nodes, comparing with the native copying model. Topological characteristics of the generated networks, such as degree distribution, average shortest-path length and clustering coefficient, are analyzed and numerized. These properties are validated with some crawled datasets of real online social networks.

关键词： online social network network evolution model degree distribution average shortest-path length clustering coefficient

Wavelength-Tunable Rectangular Pulse Dissipative Soliton Operation of an Erbium-Doped Mode-Locked Fiber Laser

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Chinese Physics Letters 2014年第4期31卷 68-71页

作者： HU Xue-Juan guo chun-yu RUAN Shuang-Chen Shenzhen Key Laboratory of Laser Engineering Key Laboratory of Advanced Optical Precision Manufacturing Technology of Guangdong Higher Education Institutes College of Electronic Science and Technology Shenzhen University Shenzhen 518060

The wavelength-tunable rectangular pulse dissipative soliton （DS） is experimentally demonstrated, for the first time to the best of our knowledge, in an erbium-doped figure-of-eight fiber laser based on the nonlinear amplifying loop mirror mode-locked technique. The proposed rectangular pulse DS fiber laser can operate in the wavelength- tunable mode-locked state from 1573.5nm to 159d.6 nm with the rotation of the polarization controllers. The achieved output wavelengths are 1573.5nm, 1576.3nm, 1586.8nm, 1590.4nm and 1594.6nm, respectively. The pulse widths of the rectangular pulse can also be tuned from ~8ns to ~24ns by adjusting the pump power. The fundamental repetition rate of the rectangular pulse DS is 1.154 MHz and the output power is 6.1d m W （at 1594.6 nm）.

关键词： WAVELENGTHS SOLITONS FIBER lasers MODE-locked lasers GAUSSIAN function

NUMERICAL SIMULATION OF A PODDED PROPULSOR IN VISCOUS FLOW

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维普期刊数据库

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Journal of Hydrodynamics 2009年第1期21卷 71-76页

作者： guo chun-yu MA Ning YANG Chen-jun State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Shanghai 200030 China

A podded propulsor in viscous flow is numerically simulated in this article. The region of fluid is divided into efficient calculation grids. The pressure and viscous force of blades, pod and strut are obtained as functions of an advance coefficient. The steady result is used as a base in the unsteady simulation to obtain a solution more quickly. The distributions of the thrust and torque fluctuations of the key blade in one revolution are obtained. The c^lculation results from the mixing plane on steady conditions are compared with those obtained from the sliding mesh model on unsteady conditions. The User-Defined Function （UDF） method is used to simulate the influence of ship hull on the non-uniform wake of the propeller.

关键词： podded propulsor propeller steady unsteady RANS

Influence of Ice Size Parameter Variation on Hydrodynamic Performance of Podded Propulsor

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China Ocean Engineering 2020年第1期34卷 30-45页

作者： guo chun-yu XU Pei WANG Chao WANG Lian-zhou ZHANG Cheng-sen College of Shipbuilding Engineering Harbin Engineering University

During ice-breaking navigation, a massive amount of crushed ice blocks with different sizes is accumulated under the hull of an ice-going ship. This ice slides into the flow field in the forward side of the podded propulsor, affecting the surrounding flow field and aggravating the non-uniformity of the propeller wake. A pulsating load is formed on the propeller, which affects the hydrodynamic performance of the podded propulsor. To study the changes in the propeller hydrodynamic performance during the ice podded propulsor interaction, the overlapping grid technique is used to simulate the unsteady hydrodynamic performance of the podded propulsor at different propeller rotation angles and different ice block sizes. Hence, the hydrodynamic blade behavior during propeller rotation under the interaction between the ice and podded propulsor is discussed. The unsteady propeller loads and surrounding flow fields obtained for ice blocks with different sizes interacting with the podded propulsor are analyzed in detail. The variation in the hydrodynamic performance during the circular motion of a propeller and the influence of ice size variation on the propeller thrust and torque are determined. The calculation results have certain reference significance for experiment-based research, theoretical calculations and numerical simulation concerning ice podded propulsor interaction.

关键词： podded propulsor ice propeller interaction hydrodynamic load overlap grid

Experimental Investigation of the Resistance Performance and Heave and Pitch Motions of Ice-Going Container Ship Under Pack Ice Conditions

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China Ocean Engineering 2018年第2期32卷 169-178页

作者： guo chun-yu XIE Chang ZHANG Jin-zhao WANG Shuai ZHAO Da-gang College of Shipbuilding Engineering Harbin Engineering UniversityHarbin 150001China Nantong COSCO KHI Ship Engineering Co.Ltd Nantong 226005China Shanghai Marine Equipment Research Institute Shanghai 200031China

In order to analyze the ice-going ship’s performance under the pack ice conditions, synthetic ice was introduced into a towing tank. A barrier using floating cylinder in the towing tank was designed to carry out the resistance experiment. The test results indicated that the encountering frequency between the ship model and the pack ice shifts towards a high-velocity point as the concentration of the pack ice increases, and this encountering frequency creates an unstable region of the resistance, and the unstable region shifts to the higher speed with the increasing concentration. The results also showed that for the same speed points, the ratio of the pack ice resistance to the open water resistance increases with the increasing concentration, and for the same concentrations, this ratio decreases as the speed increases. Motion characteristics showed that the mean value of the heave motion increases as the speed increases, and the pitch motion tends to increase with the increasing speed. In addition, the total resistance of the fullscale was predicted.

关键词： synthetic ice pack ice concentration heave pitch peak collision value

Numerical Simulation on the Resistance Performance of Ice-Going Container Ship Under Brash Ice Conditions

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China Ocean Engineering 2018年第5期32卷 546-556页

作者： guo chun-yu ZHANG Zuo-tian TIAN Tai-ping LI Xia-yan ZHAO Da-gang College of Shipbuilding Engineering Harbin Engineering University SUMEC Marine Co. Ltd.

Ice resistance prediction is a critical issue in the preliminary design of ships navigating brash ice conditions, which is closely related to the safety of a ship to navigate encounter brash ice, and has significant effects on the kinds of propellers and motor power needed. In research on this topic, model tests and full-scale tests on ships have thus far been the primary approaches. In recent years, the application of the finite element method(FEM) has also attracted interest. Some researchers have conducted numerical simulations on ship–ice interactions using the fluid–structure interaction(FSI) method. This study used this method to predict and analyze the resistance of an ice-going ship, and compared the results with those of model ship tests conducted in a towing tank with synthetic ice to discuss the feasibility of the FEM. A numerical simulation and experimental methods were used to predict the brash ice resistance of an ice-going container ship model in a condition with three concentrations of brash ice(60%, 80%, and 90%). A comparison of the results yielded satisfactory agreement between the numerical simulation and the experiments in terms of both observed phenomena and resistance values, indicating that the proposed numerical simulation has significant potential for use in related studies in the future.

关键词： brash ice resistance fluid–structure interaction(FSI) finite element method(FEM) numerical simulation model ship test

Numerical Simulation and Experimental Research on Hydrodynamic Performance of Propeller with Varying Shaft Depths

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China Ocean Engineering 2014年第2期28卷 271-282页

作者：郭春雨赵大刚孙瑜 College of Shipbuilding Engineering Harbin Engineering University

In order to study hydrodynamic performance of a propeller in the free surface, the numerical simulation and open-water experiments are carried out with varying shaft depths of propeller. The influences of shaft depths of a propeller on thrust and torque coefficient in calm water are mainly studied. Meanwhile, this paper also studies the propeller air-ingestion under special working conditions by experiment and theoretical calculation method, and compares the calculation results and experimental results. The results prove that the theoretical calculation model used in this paper can imitate the propeller air-ingestion successfully. The successful phenomenon simulation provides an essential theoretical basis to understand the physical essence of the propeller air-ingestion.

关键词： propulsive performance depth of propeller shaft free surface air-ingestion

Q-Switched Thulium-Doped Domestic Silica Fiber Laser

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Chinese Physics Letters 2011年第4期28卷 112-114页

作者： HU Hui DU Ge-guo YAN Pei-Guang ZHAO Jun-Qing guo chun-yu RUAN Shuang-Chen Shenzhen Key Laboratory of Laser Engineering College of Electronic Science and TechnologyShenzhen UniversityShenzhen 518060

We report a cladding-pumped Tm^(3+)-doped domestic silica fiber laser operated at 2pm and actively Q-switched with an acousto-optic *** trains are obtained as pumped by a 785nm laser *** maximum average output power is *** power up to 4.2kW and pulse energy up to 840μJ are obtained with the pulse duration of 200ns produced at a repetition rate of 1 *** laser performance is studied under different repetition rates and pump ***,we give some discussion.

关键词： pumped laser pulse