Numerical Simulation and Experimental Validation on the Surf-Riding and Broaching of a Fishing Vessel

2016 ◽  
Author(s):  
Liwei Yu ◽  
Ning Ma ◽  
Sheming Fan ◽  
Peiyuan Feng ◽  
Xiechong Gu
Keyword(s):  
Numerical Simulation ◽  
Numerical Simulations ◽  
Model Test ◽  
Periodic Motion ◽  
Following Seas ◽  
Weakly Nonlinear ◽  
Model Experiments ◽  
Time Histories ◽  
Wave Heights ◽  
Surf Riding

Model experiments and numerical simulations on the surf-riding and broaching in following seas of a 42.5m long purse seiner are conducted. Firstly, the free running model experiments with various ship speeds and wave heights are performed in the towing tank to reproduce the phenomena of surf-riding and broaching. Then, the 6-DOF weakly nonlinear unified model is applied to simulate the motions of the purse seiner with the same cases as the model experiments. Through the comparison between results of model test and numerical simulation, the occurrence conditions of periodic motion, surf-riding and broaching are roughly determined. Finally, it is found that although it is difficult for the numerical simulations to get the same time histories as model tests, the modes of motion (periodic motion, surf-riding or broaching) obtained from the numerical simulations agree well qualitatively and quantitatively in part with the model test results.

Towards Numerical Simulation and Model Test Verifications for an Analytical Model of Tubular Member Under Lateral Impact Scenario

2016 ◽  
Author(s):  
Zhiqiang Hu ◽  
Chao Jiang ◽  
Kun Liu
Keyword(s):  
Numerical Simulation ◽  
Numerical Simulations ◽  
Model Test ◽  
Analytical Method ◽  
High Speed ◽  
Impact Force ◽  
Structural Deformation ◽  
Resistance Force ◽  
Lateral Impact ◽  
Jacket Platform

Tubular member of jacket platform has the possibility of being struck by the service ship under a lateral impact scenario. An analytical theoretical method has been proposed to predict the structural deformation and the resistance force. This paper addresses a study on the verifications for this analytical method, through numerical simulation and model test methods. The analytical method was proposed based on a new structural sectional deformation mode, which considers both of the local denting and global bending deformation. The analytical method is briefly introduced. The verification work includes three steps. Firstly, a model test was conducted, on purpose of obtaining the structural deformation and the resistance force under the lateral impact scenario when a model tubular member was struck by a wedge hammer. In the test, the tubular member was fixed at both ends and the wedge hammer hit at its middle position. A high speed camera was used to record the instantaneous motion track of the hammer, and with the motion track data, the striking force and the indentation can be obtained. Then, a curve of impact force vs. indentation in time series was got. Secondly, the numerical simulations were conducted to simulate the corresponding impact scenario. The code LS_DYNA was used. The curve of impact force vs. indentation was also obtained. Finally, a comparison study was made, to verify the accuracy of the analytical theoretical model, and it is proved that the curves match well. Furthermore, four more cases were conducted by numerical simulations, to assess the feasibility of the analytical method on prototype scantling using for the tubular member of jacket platform.

Numerical Simulation on Motion Responses of the Tsunami-Induced Grounding on a Wharf of Floating Structures Using the MPS Method

2008 ◽  
Author(s):  
Koichi Masuda ◽  
Tomoki Ikoma ◽  
Mitsuhiro Masuda ◽  
Yuta Suzuki
Keyword(s):  
Numerical Simulation ◽  
Solitary Wave ◽  
Numerical Simulations ◽  
Experimental Results ◽  
Floating Body ◽  
Floating Structures ◽  
Mps Method ◽  
Model Experiments ◽  
Motion Responses ◽  
Moving Particle

The present paper describes the application of the moving particle semi-implicit method to a prediction of tsunami-induced grounding of floating structures in the vicinity of wharfs. Effectiveness of the application is verified. Solitary wave have been applied to simulated tsunamis in numerical simulation and to the model experiments. A pontoon type floating body has been used to floating structures in numerical simulations using the MPS method. The present numerical results have been compared with the experimental results and the applicability of MPS method has been discussed. Further, after the grounding, the characteristics of gliding distance of floating body on the wharf have been discussed.

Study on Drifting Distance and Collision Force of Floating Vessels Run on Apron by Tsunami

2009 ◽  
Author(s):  
Koichi Masuda ◽  
Takujiro Miyamoto ◽  
Tomoki Ikoma ◽  
Mitsuhiro Masuda
Keyword(s):  
Numerical Simulation ◽  
Solitary Wave ◽  
Numerical Simulations ◽  
Experimental Results ◽  
Floating Body ◽  
Floating Structures ◽  
Mps Method ◽  
Model Experiments ◽  
Moving Particle ◽  
Collision Force

The present paper describes the application of the moving particle semi-implicit method to a prediction of drifting distance and collision force of floating vessels run on wharf by tsunami. Effectiveness of the application is verified. Solitary wave have been applied to simulated tsunamis in numerical simulation and to the model experiments. A pontoon type floating body has been used to floating structures in numerical simulations using the MPS method. The present numerical results have been compared with the experimental results and the applicability of MPS method has been discussed. Further, after the running on wharf by tsunami, the characteristics of drifting distance and collision force of floating body on the wharf have been discussed.

Joint High Speed Sealift (JHSS) Segmented Model Test Data Analysis and Validation of Numerical Simulations

2012 ◽  
Author(s):  
Dominic Piro ◽  
Kyle A. Brucker ◽  
Thomas T. O'Shea ◽  
Donald Wyatt ◽  
Douglas Dommermuth ◽  
...  
Keyword(s):  
Data Analysis ◽  
Numerical Simulations ◽  
Test Data ◽  
Model Test ◽  
High Speed ◽  
Segmented Model

scholarly journals Wind shear over the Nice Côte d'Azur airport: case studies

2013 ◽  
Vol 13 (9) ◽  
pp. 2223-2238 ◽  
Author(s):  
A. Boilley ◽  
J.-F. Mahfouf
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Numerical Simulations ◽  
Wind Shear ◽  
Horizontal Wind ◽  
Wind Profiler ◽  
Measurement Campaign ◽  
Wind Lidar ◽  
Real Time Applications ◽  
Wind Shears

Abstract. The Nice Côte d'Azur international airport is subject to horizontal low-level wind shears. Detecting and predicting these hazards is a major concern for aircraft security. A measurement campaign took place over the Nice airport in 2009 including 4 anemometers, 1 wind lidar and 1 wind profiler. Two wind shear events were observed during this measurement campaign. Numerical simulations were carried out with Meso-NH in a configuration compatible with near-real time applications to determine the ability of the numerical model to predict these events and to study the meteorological situations generating an horizontal wind shear. A comparison between numerical simulation and the observation dataset is conducted in this paper.

A State-Space Approach to the Synthesis of Random Vertical and Crosslevel Rail Irregularities

1990 ◽  
Vol 112 (1) ◽  
pp. 83-87 ◽  
Author(s):  
R. H. Fries ◽  
B. M. Coffey
Keyword(s):  
Numerical Simulation ◽  
White Noise ◽  
State Space ◽  
Spectral Characteristics ◽  
The State ◽  
Second Derivatives ◽  
Time Histories ◽  
Sample Interval ◽  
Rail Irregularities ◽  
Derivatives Of

Solution of rail vehicle dynamics models by means of numerical simulation has become more prevalent and more sophisticated in recent years. At the same time, analysts and designers are increasingly interested in the response of vehicles to random rail irregularities. The work described in this paper provides a convenient method to generate random vertical and crosslevel irregularities when their time histories are required as inputs to a numerical simulation. The solution begins with mathematical models of vertical and crosslevel power spectral densities (PSDs) representing PSDs of track classes 4, 5, and 6. The method implements state-space models of shape filters whose frequency response magnitude squared matches the desired PSDs. The shape filters give time histories possessing the proper spectral content when driven by white noise inputs. The state equations are solved directly under the assumption that the white noise inputs are constant between time steps. Thus, the state transition matrix and the forcing matrix are obtained in closed form. Some simulations require not only vertical and crosslevel alignments, but also the first and occasionally the second derivatives of these signals. To accommodate these requirements, the first and second derivatives of the signals are also generated. The responses of the random vertical and crosslevel generators depend upon vehicle speed, sample interval, and track class. They possess the desired PSDs over wide ranges of speed and sample interval. The paper includes a comparison between synthetic and measured spectral characteristics of class 4 track. The agreement is very good.

Stefan Number-Insensitive Numerical Simulation of the Enthalpy Method for Stefan Problems Using the Space-Time Conservation Element and Solution Element Method

2004 ◽  
Author(s):  
Anahita Ayasoufi ◽  
Theo G. Keith ◽  
Ramin K. Rahmani
Keyword(s):  
Numerical Simulation ◽  
Phase Change ◽  
Numerical Simulations ◽  
Latent Heat ◽  
Space Time ◽  
Enthalpy Method ◽  
Stefan Problems ◽  
Stefan Number ◽  
Original Scheme ◽  
Solution Element

An improvement is introduced to the conservation element and solution element (CE/SE) phase change scheme presented previously. The improvement addresses a well known weakness in numerical simulations of the enthalpy method when the Stefan number, (the ratio of sensible to latent heat) is small (less than 0.1). Behavior of the improved scheme, at the limit of small Stefan numbers, is studied and compared with that of the original scheme. It is shown that high dissipative errors, associated with small Stefan numbers, do not occur using the new scheme.

Pneumatic pulsator design as an example of numerical simulations in engineering applications

2012 ◽  
Vol 2 (1) ◽  
Author(s):  
Krzysztof Wołosz ◽  
Jacek Wernik
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Cast Iron ◽  
Numerical Simulations ◽  
Stress Analysis ◽  
Aluminium Alloy ◽  
Loose Material ◽  
Engineering Applications ◽  
Pressure Losses ◽  
Pneumatic Impact

AbstractThe paper presents the part of the investigation that has been carried out in order to develop the pneumatic pulsator which is to be employed as an unblocking device at lose material silo outlets. The part of numerical simulation is reported. The fluid dynamics issues have been outlined which are present during supersonic airflow thought the head of the pulsator. These issues describe the pneumatic impact phenomenon onto the loose material bed present in the silo to which walls the pulsator is assembled. The investigation presented in the paper are industrial applicable and the result is the working prototype of the industrial pneumatic pulsator. The numerical simulation has led to change the piston shape which is moving inside the head of the pulsator, and therefore, to reduce the pressure losses during the airflow. A stress analysis of the pulsator controller body has been carried out while the numerical simulation investigation part of the whole project. The analysis has made possible the change of the controller body material from cast iron to aluminium alloy.

scholarly journals Focusing of long waves with finite crest over constant depth

2013 ◽  
Vol 469 (2153) ◽  
pp. 20130015 ◽  
Author(s):  
Utku Kânoğlu ◽  
Vasily V. Titov ◽  
Baran Aydın ◽  
Christopher Moore ◽  
Themistoklis S. Stefanakis ◽  
...  
Keyword(s):  
Source Region ◽  
Wave Theory ◽  
Long Waves ◽  
Constant Depth ◽  
Large Wave ◽  
Weakly Nonlinear ◽  
Scaling Relationships ◽  
2011 Japan Tsunami ◽  
Wave Heights ◽  
Run Up

Tsunamis are long waves that evolve substantially, through spatial and temporal spreading from their source region. Here, we introduce a new analytical solution to study the propagation of a finite strip source over constant depth using linear shallow-water wave theory. This solution is not only exact, but also general and allows the use of realistic initial waveforms such as N -waves. We show the existence of focusing points for N -wave-type initial displacements, i.e. points where unexpectedly large wave heights may be observed. We explain the effect of focusing from a strip source analytically, and explore it numerically. We observe focusing points using linear non-dispersive and linear dispersive theories, analytically; and nonlinear non-dispersive and weakly nonlinear weakly dispersive theories, numerically. We discuss geophysical implications of our solutions using the 17 July 1998 Papua New Guinea and the 17 July 2006 Java tsunamis as examples. Our results may also help to explain high run-up values observed during the 11 March 2011 Japan tsunami, which are otherwise not consistent with existing scaling relationships. We conclude that N -waves generated by tectonic displacements feature focusing points, which may significantly amplify run-up beyond what is often assumed from widely used scaling relationships.

Numerical Simulation of Ship Collision and Validations With Experimental Results

2021 ◽  
Author(s):  
Xiangbiao Wang ◽  
Chun Bao Li ◽  
Ling Zhu
Keyword(s):  
Numerical Simulation ◽  
Model Test ◽  
Structural Damage ◽  
Added Mass ◽  
Ship Motion ◽  
Time Dependent ◽  
Structural Deformation ◽  
Structure Interaction ◽  
Ship Collision ◽  
Good Agreement

Abstract Ship collision accidents occur from time to time in recent years, and this would cause serious consequences such as casualties, environmental pollution, loss of cargo on board, damage to the ship and its equipment, etc. Therefore, it is of great significance to study the response of ship motion and the mechanism of structural damage during the collision. In this paper, model experiments and numerical simulation are used to study the ship-ship collision. Firstly, the Coupled Eulerian-Lagrangian (CEL) was used to simulate the fluid-structure interaction for predicting structural deformation and ship motion during the normal ship-ship collision. Meanwhile, a series of model tests were carried out to validate the numerical results. The validation presented that the CEL simulation was in good agreement with the model test. However, the CEL simulation could not present the characteristics the time-dependent added mass.

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