A Fundamental Study on the Damage of Wash Up to the Quay of the Moored Vessel in Tsunamis Using the MPS Method Considered the Fender Influences

2018 ◽  
Author(s):  
Mitsuhiro Masuda ◽  
Kiyokazu Minami ◽  
Koichi Masuda
Keyword(s):  
Numerical Simulation ◽  
Three Dimensional ◽  
Simulation Method ◽  
Implicit Method ◽  
Spring Model ◽  
Mooring Lines ◽  
Fundamental Study ◽  
Protection Measures ◽  
Mps Method ◽  
Moving Particle

In the case of vessels are moored at the quay, the drift and the wash up to the quay due to the broke of mooring lines is occurred by the tsunamis. In the previous study, the authors are examined to the applicability of the proposed tsunami protection measures as the install more mooring lines (IMML) and the floating tsunami protection wharf (FTPW). However, the Fender influences were not considered in previous authors studies. In this study, the fender influences are considered on the numerical simulation. The three-dimensional MPS (Moving Particle Semi-implicit) method is used as numerical simulation method. The linear compressing spring model is used as the fender model. The fender influences were investigated against the influences of tsunami protection measures using IMML and the damage status of vessel.

A Fundamental Study on Tsunami Protection Measures for a Vessel Moored at a Wharf Considering the Backwash Influence

2019 ◽  
Author(s):  
Mitsuhiro Masuda ◽  
Kiyokazu Minami ◽  
Koichi Masuda
Keyword(s):  
Three Dimensional ◽  
Dam Break ◽  
Implicit Method ◽  
Protection Measure ◽  
Fundamental Study ◽  
Protection Measures ◽  
Moving Particle ◽  
Damage Protection ◽  
Flow Velocities

Abstract When a tsunami attacks in harbors, a vessel moored at a wharf is occurred a serious damage. The first wave of the tsunami has two forms and those are called the leading wave and the backwash. And, it is difficult to predict the form of the first wave of tsunamis. Authors have been studying about damage protection measures against the leading wave of vessels moored at wharves. However, it is also necessary that a damage protection measure against the backwash of vessels moored at wharves is considered. In this study, it is examined the damage status of a vessel at a wharf due to the backwash. Then, it is examined the influence of the backwash to the author’s proposal tsunami protection measures. The three dimensional MPS (Moving Particle Semi-implicit) method is used. The Backwash is simulated as the dam break phenomenon. Outflow angles, flow velocities, mooring conditions and with and without of tsunami protection measures are considered.

Effects of Wall Condition of a Plunging Body on Splash

2011 ◽  
Author(s):  
Masao Yokoyama ◽  
Yoshihiro Kubota ◽  
Osamu Mochizuki
Keyword(s):  
Numerical Simulation ◽  
Implicit Method ◽  
Water Tank ◽  
Air Cavity ◽  
Slip Ratio ◽  
Mps Method ◽  
Swelling Degree ◽  
Living Things ◽  
Wall Condition ◽  
Moving Particle

Splashes generated by hydrogel sphere were simulated numerically and experimentally for investigating the effects of slip like mucus of living things. Numerical simulation using MPS (Moving Particle Semi-implicit) method was carried out. We defined the slip ratio as the swelling degree of hydrogel and installed the slip ratio into the MPS method. The swelling degree is the ratio of the weight of water against that of hydrogel. We simulated the splashes generated by the hydrogel spheres which had the different swelling degree plunging into water. As the evaluation of swelling degree on the surface of actual hydrogel spheres we also tested by using the hydrogel spheres plunging into water experimentally. The height of splash as a result of reaction of the air cavity became higher according to the increase of the swelling degree. The speed of hydrogel sphere sinking in water tank was also quicker in the numerical simulation. The reason of these results was that the velocity of water around the hydrogel sphere became quicker due to the slip on the surface.

Numerical Simulation Method for Damaged Ships Under Flooding Condition

2013 ◽  
Author(s):  
Hirotada Hashimoto ◽  
Kouki Kawamura ◽  
Makoto Sueyoshi
Keyword(s):  
Numerical Simulation ◽  
Simulation Method ◽  
Mps Method ◽  
Strip Method ◽  
Numerical Simulation Method ◽  
Damage Stability ◽  
Calm Water ◽  
Good Potential ◽  
Moving Particle ◽  
Method Model

Securing the survivability under flooding condition is one of the most important subjects in ship design. For realizing advanced assessment of damage stability, a numerical simulation method for damaged ships is developed by combining the moving particle semi-implicit method (MPS method) and the ordinary strip method based on potential flow theory. In this method, the flow field around the damaged hull including damaged compartments is solved by the MPS method and that around the intact hull is done by the strip method, separately. In order to validate the proposed method, model experiments are conducted for a damaged pure car and truck carrier in calm water and regular beam waves. Then numerical results of the ship motion and the flooding into the damaged compartment are compared with them. As a result, it is demonstrated that the proposed method has good potential for the prediction of dynamic behaviours of damaged ships under flooding condition.

A Fundamental Study on the Applicability of the Floating Large Size Tsunami Shelter

2016 ◽  
Author(s):  
Takuma Kishi ◽  
Kiyokazu Minami ◽  
Mitsuhiro Masuda
Keyword(s):  
Numerical Simulation ◽  
Implicit Method ◽  
Water Tank ◽  
Fundamental Study ◽  
Collision Model ◽  
Large Size ◽  
Tank Experiment ◽  
Water Tank Experiment ◽  
Moving Particle ◽  
Run Up

A floating large-size tsunami shelter (FLTS) has been proposed. The shelter can evacuate more than 1500 people to evacuate from run-up tsunami. The floating tsunami shelter can be lifted by buoyancy when tsunami hitting. In this study, First, Authors assumed Principal specifications of the FLTS from estimation of damage and second we evaluated the validity and safety of a floating large size tsunami shelter using the mooring dolphin by water tank experiment and numerical simulation that is moving particle semi-implicit method (MPS). As a result, enough performance was recognized. The mooring of dolphin was reduced the motion against 10m height tsunami than no moored. However it became clear about the numerical simulation that improvement was more necessary. In particular, the collision model was necessary improved by the existing model.

scholarly journals Strata behavior and control strategy of backfilling collaborate with caving fully-mechanized mining

2020 ◽  
Vol 12 (1) ◽  
pp. 703-717
Author(s):  
Yin Wei ◽  
Wang Jiaqi ◽  
Bai Xiaomin ◽  
Sun Wenjie ◽  
Zhou Zheyuan
Keyword(s):  
Numerical Simulation ◽  
Control Strategy ◽  
Three Dimensional ◽  
Simulation Method ◽  
Mine Pressure ◽  
Hydraulic Support ◽  
Transition Area ◽  
Pressure Concentration ◽  
Strata Behavior ◽  
And Control

AbstractThis article analyzes the technical difficulties in full-section backfill mining and briefly introduces the technical principle and advantages of backfilling combined with caving fully mechanized mining (BCCFM). To reveal the strata behavior law of the BCCFM workface, this work establishes a three-dimensional numerical model and designs a simulation method by dynamically updating the modulus parameter of the filling body. By the analysis of numerical simulation, the following conclusions about strata behavior of the BCCFM workface were drawn. (1) The strata behavior of the BCCFM workface shows significant nonsymmetrical characteristics, and the pressure in the caving section is higher than that in the backfilling section. φ has the greatest influence on the backfilling section and the least influence on the caving section. C has a significant influence on the range of abutment pressure in the backfilling section. (2) There exits the transition area with strong mine pressure of the BCCFM workface. φ and C have significant effect on the degree of pressure concentration but little effect on the influence range of strong mine pressure in the transition area. (3) Under different conditions, the influence range of strong mine pressure is all less than 6 m. This article puts forward a control strategy of mine pressure in the transition area, which is appropriately improving the strength of the transition hydraulic support within the influence range (6 m) in the transition area according to the pressure concentration coefficient. The field measurement value of Ji15-31010 workface was consistent with numerical simulation, which verifies the reliability of control strategy of the BCCFM workface.

scholarly journals Study of the Effect of Centrifugal Force on Rotor Blade Icing Process

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Zhengzhi Wang ◽  
Chunling Zhu
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Force ◽  
Rotor Blade ◽  
Flow Direction ◽  
Three Dimensional ◽  
Simulation Method ◽  
Two Phase ◽  
Numerical Simulation Method ◽  
Calculation Results ◽  
Flow Field Characteristics

In view of the rotor icing problems, the influence of centrifugal force on rotor blade icing is investigated. A numerical simulation method of three-dimensional rotor blade icing is presented. Body-fitted grids around the rotor blade are generated using overlapping grid technology and rotor flow field characteristics are obtained by solving N-S equations. According to Eulerian two-phase flow, the droplet trajectories are calculated and droplet impingement characteristics are obtained. The mass and energy conservation equations of ice accretion model are established and a new calculation method of runback water mass based on shear stress and centrifugal force is proposed to simulate water flow and ice shape. The calculation results are compared with available experimental results in order to verify the correctness of the numerical simulation method. The influence of centrifugal force on rotor icing is calculated. The results show that the flow direction and distribution of liquid water on rotor surfaces change under the action of centrifugal force, which lead to the increasing of icing at the stagnation point and the decreasing of icing on both frozen limitations.

Calculation and Design Method Study of the Coil-Wound Heat Exchanger

2014 ◽  
Vol 1008-1009 ◽  
pp. 850-860 ◽  
Author(s):  
Zhou Wei Zhang ◽  
Jia Xing Xue ◽  
Ya Hong Wang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Exchanger ◽  
Design Method ◽  
Fluid Velocity ◽  
Exchange Process ◽  
Three Dimensional ◽  
Simulation Method ◽  
Physical Parameters ◽  
Numerical Result

A calculation method for counter-current type coil-wound heat exchanger is presented for heat exchange process. The numerical simulation method is applied to determine the basic physical parameters of wound bundles. By controlling the inlet fluid velocity varying in coil-wound heat exchanger to program and calculate the iterative process. The calculation data is analyzed by comparison of numerical result and the unit three dimensional pipe bundle model was built. Studies show that the introduction of numerical simulation can simplify the pipe winding process and accelerate the calculation and design of overall configuration in coil-wound heat exchanger. This method can be applied to the physical modeling and heat transfer calculation of pipe bundles in coil wound heat exchanger, program to calculate the complex heat transfer changing with velocity and other parameters, and optimize the overall design and calculation of spiral bundles.

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