Autor: Ma, W.W. - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Simulation on vessel intelligent collision avoidance based on artificial fish swarm algorithm
Autorzy:: Li, W.
Ma, W.
Powiązania:: https://bibliotekanauki.pl/articles/260153.pdf
Data publikacji:: 2016
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:: simulation
collision avoidance
artificial fish swarm algorithm
Opis:: TAs the rapid development of the ship equipments and navigation technology, vessel intelligent collision avoidance theory was researched world widely. Meantime, more and more ship intelligent collision avoidance products are put into use. It not only makes the ship much safer, but also lighten the officers work intensity and improve the ship’s economy. The paper based on the International Regulation for Preventing Collision at sea and ship domain theories, with the ship proceeding distance when collision avoidance as the objective function, through the artificial fish swarm algorithm to optimize the collision avoidance path, and finally simulates overtaking situation, crossing situation and head-on situation three classic meeting situation of ships on the sea by VC++ computer language. Calculation and simulation results are basically consistent with the actual situation which certifies that its validity.
Źródło:: Polish Maritime Research; 2016, S 1; 138-143
1233-2585
Pojawia się w:: Polish Maritime Research
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Numerical research of the viscous effect of the bilge keel on the damping moment
Autorzy:: Deng, R.
Duan, W.
Ma, S.
Ma, Y.
Powiązania:: https://bibliotekanauki.pl/articles/258868.pdf
Data publikacji:: 2015
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:: calculation model
viscous code
phase difference
damping mpment
bilge keel
Opis:: Bilge keels are effective passive devices in mitigating the rolling motion, and the usage of them covers almost all the sea going vessels. This paper focuses on the viscous effect of the bilge keel, ignored the effect of the free surface and the effect of the ship hull, for the general viscous characteristic of the bilge keel. In order to investigate the viscous effect of the bilge keel on the total damping moment, a special 2 dimensional numerical model, which includes a submerged cylinder with and without bilge keels, is designed for the simulation of forced rolling. Three important factors such as bilge keels width, rolling periods, as well as maximal rolling angles are taken into account, and the viscous flow field around the cylinder is simulated by some codes based on the viscous method in different conditions, in which the three factors are coupled. Verification and validation based on the ITTC method are performed for the cylinder without bilge keels in the conditions of different rolling periods and maximal rolling angles. The primary calculation of damping moment induced by the cylinder with 0mm, 4mm, and 10mm width bilge keels shows some interesting results, and a systematic analysis is conducted. The analysis of the damping moment components suggests there is phase difference between the damping moment induced by the cylinder and the bilge keels, and when the bilge keels width reaches a special size, the total damping moment is mitigated. The calculation of the damping moments induced by the cylinder with some larger bilge keels are also performed, and the results suggest that, the damping moment induced by the bilge keels is increased rapidly and becomes the dominant part in the total damping moment while the width of the bilge keels are increased, but the damping moment induced by the cylinder is not changed significantly. Some illustration of the vortices formation and shedding is included, which is the mechanism of the damping moment caused by the bilge keels. The present work shows an interesting problem, and it is useful for the bilge keel design.
Źródło:: Polish Maritime Research; 2015, S 1; 67-74
1233-2585
Pojawia się w:: Polish Maritime Research
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: 3-D simulation of vertical-axial tidal current turbine
Autorzy:: Zhang, Z.
Ma, Y.
Jiang, J.
Liu, W.
Ma, Q.
Powiązania:: https://bibliotekanauki.pl/articles/260421.pdf
Data publikacji:: 2016
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:: tidal current energy
vertical-axial turbine
hydrodynamic performance
CFD
numerical simulation
3-D effect
Opis:: Vertical-axial tidal current turbine is the key for the energy converter, which has the advantages of simple structure, adaptability to flow and uncomplex convection device. It has become the hot point for research and application recently. At present, the study on the hydrodynamic performance of vertical-axial tidal current turbine is almost on 2-D numerical simulation, without the consideration of 3-D effect. CFD (Computational Fluid Dynamics) method and blade optimal control technique are used to improve accuracy in the prediction of tidal current turbine hydrodynamic performance. Numerical simulation of vertical-axial tidal current turbine is validated. Fixed and variable deflection angle turbine are comparatively studied to analysis the influence of 3-D effect and the character of fluid field and pressure field. The method, put the plate on the end of blade, of reduce the energy loss caused by 3-D effect is proposed. The 3-D CFD numerical model of vertical-axial tidal current turbine hydrodynamic performance in this study may provide theoretical, methodical and technical reference for the optimal design of turbine.
Źródło:: Polish Maritime Research; 2016, 4; 73-83
1233-2585
Pojawia się w:: Polish Maritime Research
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Test studies of the resistance and seakeeping performance of a trimaran planing hull
Autorzy:: Ma, W.
Sun, H.
Zou, J.
Zhuang, J.
Powiązania:: https://bibliotekanauki.pl/articles/259495.pdf
Data publikacji:: 2015
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:: trimaran planing hull
appendix
resistance
seakeeping
model test
Opis:: Towing tank tests in calm water were performed on a trimaran planing hull to verify its navigational properties with different displacements and centres of gravity, as well as to assess the effects of air jets and bilge keels on the hull’s planing capabilities, and to increase the longitudinal stability of the hull. Hydrostatic roll tests, zero speed tests, and sea trials in the presence of regular waves were conducted to investigate the hull’s seakeeping ability. The test results indicate that the influence of the location of the centre of gravity on the hull resistance is similar to that of a normal trimaran planing hull; namely, moving the centre of gravity backward will reduce the resistance but lower the stability. Bilge keels improve the longitudinal stability but slightly affect the resistance, and the presence of air jets in the hull’s channels decreases the trim angle and increases heaving but has little effect on the resistance. Frequent small-angle rolling occurs in waves. The heaving and pitching motions peak at the encounter frequency of , and the peaks increase with velocity and move towards greater encounter frequencies. When the encounter frequency exceeds, the hull motion decreases, which leads to changes in the navigation speed and frequency.
Źródło:: Polish Maritime Research; 2015, 1; 22-27
1233-2585
Pojawia się w:: Polish Maritime Research
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Test research on the resistance performance of high-speed trimaran planing hull
Autorzy:: Ma, W.
Sun, H.
Zou, J.
Yang, H.
Powiązania:: https://bibliotekanauki.pl/articles/259708.pdf
Data publikacji:: 2013
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:: trimaran planing hull
side hulls
high speed
step
resistance
model test
Opis:: In order to identify high-speed navigation ability of trimaran planing hull, as well as investigate the characteristics of its resistance and hull form, ship model tests were conducted to measure resistance, trim and heaving under different displacements and gravity centre locations. The test results were then used to study the influence of spray strips on resistance and sea-keeping qualities. Moreover, different planning surfaces were compared in the model tests which helped to look into influence of steps on hull resistance and its moving position. Also, the resistance features of monohull and trimaran planing hulls, both with and without steps, were compared to each other. From the tests it can be concluded that: the two auxiliary side hulls increase aerodynamic lift at high-speed motion, which improves the hydrodynamic performance; the trimaran planing hull has also excellent longitudinal stability and low wave-making action; when Fr∇> 8, its motion is still stable and two distinct resistance peaks and two changes of sailing state (the second change is smaller) appear; spray strips are favourable for sea-keeping qualities at high speed. The change trends before the second resistance peak as to the resistance and sailing behaviour of trimaran planing hull without steps are the same as for monohull planing hull without steps. but when steps in both hulls exist the change trends are different; more specifically: trimaran planing hull with steps has only one resistance peak and its resistance increases along with its speed increasing, and the resistance is improved at the increasing speed as the number of steps increases.
Źródło:: Polish Maritime Research; 2013, 4; 45-51
1233-2585
Pojawia się w:: Polish Maritime Research
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: An optimization approach to the intermodal transportation network in fruit cold chain, considering cost, quality degradation and carbon dioxide footprint
Autorzy:: Ma, Q.
Wang, W.
Peng, Y.
Song, X.
Powiązania:: https://bibliotekanauki.pl/articles/260179.pdf
Data publikacji:: 2018
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:: intermodal transport network
quality model
refrigerated container
fruit cold chain
integer linear programming
Opis:: This model optimizes port hinterland intermodal refrigerated container flows , considering both cost and quality degradation, which is distinctive from the previous literature content in a way that it quantifies the influence of carbon dioxide (CO2) emission in different setting temperature on intermodal network planning. The primary contribution of this paper is that the model is beneficial not only to shippers and customers for the novel service design, but also offer , for policy-makers of the government, insights to develop inland transport infrastructures in consideration of intermodal transportation. The majority of models of multimodal system have been established with an objective of cost minimization for normal commodities. As the food quality is possible to be influenced by varying duration time required for the storage and transportation, and transportation accompanied with refrigeration producing more CO2 emission, this paper aims to address cost minimization and quality degradation minimization within the constraint of CO2 footprint. To achieve this aim, we put the quality degradation model in a mixed-integer linear programming model used for intermodal network planning for cold chain. The example of Dalian Port and Yingkou Port offer insight into trade-offs between transportation temperature and transport mode considering CO2 footprint. Furthermore, the model can offer a useful reference for other regions with the demand for different imported food, which requires an uninterrupted cold chain during the transportation and storage.
Źródło:: Polish Maritime Research; 2018, 1; 61-69
1233-2585
Pojawia się w:: Polish Maritime Research
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Numerical simulations of linearly stratified flow past submerged bodies
Autorzy:: Ma, W.
Li, Y.
Ding, Y.
Hu, K.
Lan, L.
Powiązania:: https://bibliotekanauki.pl/articles/259150.pdf
Data publikacji:: 2018
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:: stratified flow
circular cylinder
internal wave
Suboff
equation of state
Opis:: In this study, a methodology was presented to predict density stratified flows in the near-field of submerged bodies. The energy equation in temperature form was solved coupled with momentum and mass conservation equations. Linear stratification was achieved by the definition of the density as a function of temperature. At first, verifications were performed for the stratified flows passing a submerged horizontal circular cylinder, showing excellent agreement with available experimental data. The ability of the method to cope with variable density was demonstrated. Different turbulence models were used for different Re numbers and flow states. Based on the numerical methods proposed in this paper, the stratified flow was studied for the real scale benchmark DAPRA Suboff submarine. The approach used the VOF method for tracing the free surface. Turbulence was implemented with a k − ω based Detached Eddy Simulation (DES) approach. The effects of submarine speed, depth and density gradient on the free surface wave pattern were quantitatively analyzed. It was shown that, with the increasing of the speed of the submarine, the wavelength and wave height of the free surface wave were gradually increasing. The wave height of the free surface wave was gradually reduced as the submarine’s depth increased. Relative to the speed and submarine depth, the changes of the gradient density gradient have negligible effects on the free surface wave field.
Źródło:: Polish Maritime Research; 2018, S 3; 68-77
1233-2585
Pojawia się w:: Polish Maritime Research
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Motion prediction of catamaran with a semisubmersible bow in wave
Autorzy:: Sun, H.
Jing, F.
Jiang, Y.
Zou, J.
Zhuang, J.
Ma, W.
Powiązania:: https://bibliotekanauki.pl/articles/258596.pdf
Data publikacji:: 2016
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:: SSB catamaran
model test
overset grid
motion region
motion response
Opis:: Compared with standard vessels, a slender catamaran with a semi-submerged bow (SSB) demonstrates superior seakeeping performance. To predict the motion of an SSB catamaran, computational fluid dynamics methods are adopted in this study and results are validated through small-scale model tests. The pitch, heave, and vertical acceleration are calculated at various wavelengths and speeds. Based on the overset grid and motion region methods, this study obtains the motion responses of an SSB catamaran in regular head waves. The results of the numerical studies are validated with the experimental data and show that the overset grid method is more accurate in predicting the motion of an SSB catamaran; the errors can be controlled within 20%. The movement data in regular waves shows that at a constant speed, the motion response initially increases and then decreases with increasing wavelength. This motion response peak is due to the encountering frequency being close to the natural frequency. Under identical sea conditions, the motion response increases with the increasing Froude number. The motion prediction results, that derive from a shortterm irregular sea state, show that there is an optimal speed range that can effectively reduce the amplitude of motion.
Źródło:: Polish Maritime Research; 2016, 1; 37-44
1233-2585
Pojawia się w:: Polish Maritime Research
Dostawca treści:: Biblioteka Nauki

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