Low Speed Ship Manoeuvrability: Mathematical Model and its Simulation

2013 ◽  
Author(s):  
Kyoung-Gun Oh ◽  
Kazuhiko Hasegawa
Keyword(s):  
Mathematical Model ◽  
Cross Flow ◽  
Hydrodynamic Forces ◽  
Point Of View ◽  
Comparison Study ◽  
Low Speed ◽  
The Mathematical Model ◽  
Yaw Moment ◽  
Sway Motion ◽  
Ship Handling

In case of offshore support vessels, it is quite important for their behaviours in low speed manoeuvrability. It is not easy to operate offshore support vessels and it raises an importance to train crew by a ship handling simulator. Therefore it is quite hot issue for ship handling simulator vendors to provide mathematical model of support vessels, but from the users’ point-of-view the model used for the simulator is not clear. Up to now some mathematical models are proposed in the literature, but the validation is not yet done carefully. For example, cross flow model is the main part for hydrodynamic force in low speed ship manoeuvring. From model ship experiments of various types of ships and from some comparison study, it is found that further discussion is necessary. In this paper, sway force and yaw moment as well as surge force will be treated in low speed condition with certain sway and yaw motions. There are many experiment results for such hydrodynamic forces and moment, especially for sway force and yaw moment, for sway motion, but those for yaw motion is quite limited. In this paper, such hydrodynamic forces and moment for both sway and yaw motions are calculated and validated with experiment results. Some manoeuvring simulation will also demonstrate which terms and/or expressions in the mathematical model are affecting the motion.

Deep and Shallow Water Low-Speed Maneuvering Tests: Comparison Between Experimental and Simulation Results

2016 ◽  
Author(s):  
Felipe Ribolla Masetti ◽  
Pedro Cardozo de Mello ◽  
Guilherme F. Rosetti ◽  
Eduardo A. Tannuri
Keyword(s):  
Mathematical Model ◽  
Small Scale ◽  
Shallow Waters ◽  
Hydrodynamic Coefficients ◽  
Low Speed ◽  
Tunnel Model ◽  
Oceanographic Research ◽  
Simulation Results ◽  
The University ◽  
The Mathematical Model

This paper presents small-scale low-speed maneuvering tests with an oceanographic research vessel and the comparison with mathematical model using the real time maneuvering simulator developed by the University of São Paulo (USP). The tests are intended to verify the behavior of the vessel and the mathematical model under transient and low speed tests. The small-scale tests were conducted in deep and shallow waters, with a depth-draft ratio equal to 1.28, in order to verify the simulator ability to represent the vessel maneuverability on both depth conditions. The hydrodynamic coefficients used in the simulator model were obtained by CFD calculations and wind tunnel model tests carried out for this vessel. Standard turning circle and accelerating turn maneuvers were used to compare the experimental and numerical results. A fair agreement was achieved for shallow and deep water. Some differences were observed mainly in the initial phase of the accelerating turn test.

The Properties of Two-Way Cartridge Valve in Water Hydraulic through Matlab/Simulink

2012 ◽  
Vol 271-272 ◽  
pp. 1073-1076
Author(s):  
Zhen Hua Duan ◽  
Zhang Yong Wu ◽  
Qing Hui Wang ◽  
Xi Wu ◽  
Cheng Zhuo Wen
Keyword(s):  
Mathematical Model ◽  
Simulation Analysis ◽  
Point Of View ◽  
Matlab Simulink ◽  
Practical Point ◽  
Structure Characteristics ◽  
Water Hydraulic ◽  
The Mathematical Model

According to the requirements of hydraulic transmission to two-way cartridge valve, and from the practical point of view a water hydraulic two-way cartridge valve was designed. Then its structure characteristics was introduced and the mathematical model was established. The simulation analysis of the water hydraulic two-way cartridge valve has been carried out through Matlab/Simulink proving that its structure was reasonable and it had good performances.

NUMERICAL AND PROGRAM IMPLEMENTATION OF A ONE-DIMENSIONAL MATHEMATICAL MODEL OF HYDRAULIC FRACTURING

2021 ◽  
Vol 7 (1) ◽  
pp. 126-145
Author(s):  
Alexey S. SHLYAPKIN ◽  
Alexey V. TATOSOV
Keyword(s):  
Mathematical Model ◽  
Hydraulic Fracturing ◽  
Program Implementation ◽  
Software Package ◽  
Import Substitution ◽  
Point Of View ◽  
Growth Potential ◽  
Design Problems ◽  
Software Market ◽  
The Mathematical Model

At present, an active policy of import substitution is being pursued, dictated by the imposed international sanctions, which creates a need for finding optimal engineering solutions, in particular, in the field of creating Russian software. In the study and design of hydraulic fracturing, they often rely on the results of modeling in specialized simulators. The appearance of the Russian products on the software market, surely, sets the correct vector of development; however, some aspects are not implemented in the existing mathematical models. The authors of this article present a model that allows considering in detail the process of movement of proppant particles in a hydraulic fracture. The chosen direction is important from the point of view of calculating the fracture cavity and refining its productivity, since the behavior of the particles has a significant effect on both the growth potential of the crack and its shape. The research methodology includes a theoretical justification of the mathematical model presented by the authors in their previous works; a description of the basic principles of selecting and constructing a numerical calculation scheme and creating a software package. The main methods of research are the methods of mathematical modeling, formed from practical problems on the estimation of geometric parameters of the crack, including the areas of continuum mechanics and fracture of solids, underground hydrodynamics. The proposed and implemented numerically mathematical model forms the basis of the authors’ software package, which allows solving the main design problems when performing hydraulic fracturing operations.

Prediction of the Damaging Flow-Induced Vibrations in Tubular Heat Exchangers With Triangular Arrays

2014 ◽  
Author(s):  
Yehia A. Khulief ◽  
Salem A. Bashmal ◽  
Sayed A. Said ◽  
Dhawi A. Al-Otaibi ◽  
Khalid M. Mansour
Keyword(s):  
Mathematical Model ◽  
Service Life ◽  
Test Section ◽  
Heat Exchangers ◽  
Cross Flow ◽  
Test Rig ◽  
Flow Rates ◽  
Tube Arrays ◽  
Flow Induced Vibrations ◽  
The Mathematical Model

The prediction of flow rates at which the vibration-induced instability takes place in tubular heat exchangers due to cross-flow is of major importance to the performance and service life of such equipment. In this paper, the semi-analytical model developed in [1] for square tube arrays was extended and utilized to study the triangular tube patterns. A laboratory test rig with instrumented test section is used to measure the fluidelastic coefficients to be used for tuning the mathematical model. The test section can be made of any bundle pattern. In this study, two test sections were constructed for both the normal triangular and the rotated triangular tube arrays. The developed scheme is utilized in predicting the onset of flow-induced instability in the two triangular tube arrays. The results are compared to those obtained for two other bundle configurations; namely the square and rotated square arrays reported in [1]. The results of the four different tube patterns are viewed in the light of TEMA predictions. The comparison demonstrated that TEMA guidelines are more conservative in all configurations considered.

Mathematical Model of the Servo Drive with Friction Wheals. Simulations and Real Object Examination Results

2013 ◽  
Vol 198 ◽  
pp. 15-20 ◽  
Author(s):  
Lukasz Fracczak
Keyword(s):  
Mathematical Model ◽  
Cardiac Surgery ◽  
Control System ◽  
Simulation Model ◽  
Degrees Of Freedom ◽  
Point Of View ◽  
Real Object ◽  
Servo Drive ◽  
Two Degrees Of Freedom ◽  
The Mathematical Model

In this paper the servo drive with friction wheels is presented. The servo drive is designed to move the automatic laparoscope tool or laparoscope camera (thereinafter laparoscope sleeve or sleeve) in two Degrees of Freedom (DOF). The description of the drive mechanism, operating principle and mathematical model of this drive is presented. Based on this model, the Control System (CS) has been created, and used to the construction of a simulation model. The simulation illustrates the proper functionality of the mathematical model of the servo drive with the described CS. This paper also presents the servo drive test stand and the most important examination results from the point of view of using them in the cardiac surgery Robin Heart robot.

scholarly journals Optimisation of a clam bunk skidder from the emission production point of view

2012 ◽  
Vol 58 (No. 4) ◽  
pp. 136-141
Author(s):  
A. Janeček ◽  
R. Adamovský
Keyword(s):  
Mathematical Model ◽  
Production System ◽  
Operating Performance ◽  
Point Of View ◽  
Optimal Rate ◽  
Simple Mathematical Model ◽  
Operation Performance ◽  
The Mathematical Model

This article presents a proposal of a simple mathematical model for minimisation of the production of extraneous substances as a function of the rate of operation performance of a production system. The model is then verified by operation tests of the Terri 2040 clam bunk skidder and by determining the system&rsquo;s optimal rate of performance from the point of view of production of SO<sub>2</sub>, HC and NO<sub>x </sub>emissions. The operation tests conducted to verify the mathematical model have confirmed that conditions can be determined for the production system at which it produces minimum emissions. Min. values of SO<sub>2</sub>, and HC were achieved at approximately the same rate of performance of the clam bunk skidder. Minimum values of NO<sub>x </sub>were achieved at significantly higher rate of performance of the equipment. At the calculated optimal rate of operating performance of the Terri 2040 clam bunk skidder, the values of the produced emissions were determined per m<sup>3</sup> of timber: SO<sub>2</sub> = 1.00035 g/m<sup>3</sup>, HC = 7.796 g/m<sup>3</sup> and NO<sub>x</sub> = 0.277 g/m<sup>3</sup>.

Simulation Model of the Thermodynamic Cycle of a Three-Cylinder Double-Acting Steam Engine

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Evzen Thoendel
Keyword(s):  
Mathematical Model ◽  
Thermodynamic Cycle ◽  
Steam Pressure ◽  
Heat Energy ◽  
Point Of View ◽  
Steam Engine ◽  
Pressure Reduction ◽  
Software Environment ◽  
The Mathematical Model ◽  
Pressure Reduction Station

Today, steam engines are used for special purposes only, for example to reduce steam pressure in pressure reduction stations, where they replace the traditional and inefficient throttling process. Throttling is the most used way to control the pressure in steam reduction stations. This way is unsatisfactory from the economical point of view, because the exergy is lost uselessly. It is a part of heat energy that can perform a work. The better way of a pressure reduction is an expansion in a backpressure turbine or in a steam engine by simultaneous transformation of the heat energy into electricity (cogeneration). This article describes the design and implementation of the mathematical model of a steam engine used as pressure regulator in a pressure reduction station. The present model is a part of a comprehensive mathematical model of a cogeneration unit and also a part of the author's doctoral thesis. The model assumes detailed mathematical description of physical processes in a steam engine and implementation in an MATLAB-SIMULINK software environment.

scholarly journals Mathematical model of the road vibrating roller

2020 ◽  
Vol 1 (1) ◽  
pp. 133-139
Author(s):  
Pavel Aleksandrovich KORCHAGIN ◽  
Keyword(s):  
Mathematical Model ◽  
Dynamic System ◽  
Road Construction ◽  
Well Being ◽  
Point Of View ◽  
Engineering Industry ◽  
Supporting Surface ◽  
The Road ◽  
Vibration Protection ◽  
The Mathematical Model

Introduction. The process of compaction of the soil foundation by a road vibrating roller is considered as the object of the study. The main purpose of vibrating rollers used in road construction is to reduce the energy consumption of the compaction process and increase the productivity of the operations performed Since the 80s of the last century, the engineering industry has noted a tendency to abstention the production of static rollers. By reducing the amplitude of oscillations or completely disconnecting the vibrator, you can get the same static modes, and accordingly the results of rolling. In addition, the reduction of dynamic impacts positively affects the physical condition of an operator of the road-building machine, stabilizes the well-being and increases productivity. Materials and methods. The mathematical model of the dynamic system “Supporting surface–roller–operator” is presented. The main components of the dynamic system are described in the form of ordered and interacting subsystems. The forces acting on the dynamic system are determined; they are sources of dynamic effects. The calculation schemes of the subsystems “Operator” and “Roller”, which are of the greatest interest from the point of view of vibration protection, are reflected. Results. The result of the work can be considered the compilation of generalized scheme of the dynamic system; calculation scheme of the dynamic system; mathematical model “Supporting surface–operator–roller”; implementation of the mathematical model in MathLab, its additional Simulink extension package. Discussion and conclusion. The presented mathematical model allows carrying out research of the processes occurring in the dynamic system “Supporting surface–roller–operator”. The most rational mathematical model can be used in the development of methods and tools aimed at improving the vibration protection system for operators of road rollers. The mathematical model of a road roller is planned to be used as a basis for creating a robotic complex with an automated control system designed to perform operations to compact coatings and foundations in road construction.

Experimental and Theoretical Hydrodynamic Forces on a Mathematical Model in Confined Waters

1983 ◽  
Vol 27 (02) ◽  
pp. 75-89
Author(s):  
Stuart B. Cohen ◽  
Robert F. Beck
Keyword(s):  
Mathematical Model ◽  
Shallow Water ◽  
Hydrodynamic Forces ◽  
Experimental Results ◽  
Hull Form ◽  
Side Force ◽  
Yaw Angle ◽  
Yaw Moment

Experimental results are given for a mathematical hull form tested in shallow water. The side force and yaw moment acting on the model due to a yaw angle, the presence of canal walls, and the interaction with another stationary mathematical shape are presented. Comparisons with linearized theories are made and, in general, found to be good.

Hydrodynamic Forces of DP Jack-Up Leg when Operating in Vicinity of Seabed

2021 ◽  
pp. 1-12
Author(s):  
Nitin D. Thulkar ◽  
Satoru Yamaguchi
Keyword(s):  
Mathematical Model ◽  
Hydrodynamic Force ◽  
Weak Link ◽  
Hydrodynamic Forces ◽  
Residual Current ◽  
Dynamic Positioning ◽  
Hydrodynamic Behavior ◽  
Sea Bottom ◽  
Jack Up ◽  
The Mathematical Model

Abstract Leg placement and removal are the two most critical operational modes for dynamically positioned jack-ups when working close to an offshore asset. Any positional deviation may lead to collision and damage to the asset. The industry operates with a weak link between the dynamic positioning (DP) system and the jacking system. Current DP systems operate without any sensors identifying the hydrodynamic force variations on the legs and spudcans, which vary between different leg and spudcan designs. When the spudcan is near to the sea bottom, the hydrodynamic force must be reported to avoid large positional deviations driven by the DP system. This article promotes a mechanism to measure these forces using Computational Fluid Dynamics (CFD) analysis to analyze the jack-up behavior, when the spudcan assembly is operating close to the sea bottom. Introduction A jack-up’s dynamic positioning (DP) control system requires minimum 23–30 minutes for the mathematical model to learn the vessel’s hydrodynamic behavior and response to the environment. Although when moving between locations, DP jack-up vessels provide time for the DP model to learn the hydrodynamic behavior, the spudcan that holds the vessel position and headings does not allow the mathematical model to learn. The residual current remains constant until the spudcan is in the seabed. As a result, the DP mathematical model-building process does not help the DP system to estimate the additional forces in the form of residual current. Soon after the spudcan detaches from the seabed, the vessel drift occurs because the vessel thrusters’ response need a rapid response of thrust and azimuth (directions). The DP system manufacturers currently use a sensorless approach to account for the hydrodynamic forces on the legs and spudcans to build a factor into the mathematical model. The jack-up DP system addresses two simultaneous forces on the legs. The leg element in the air is subject to aerodynamic effects and the leg and spudcan elements in the water are subject to hydrodynamic effects. DP systems currently use drag coefficients (Cd) to compute drag forces, however the hydrodynamic force variations during the complete lowering and raising processes are never completely considered. This weak link in the overall operation leads to positional error and is generally unrecognized by the vessel operators. The risk falls to DP officer and the jacking master to handle. The DP and jacking simultaneous operations mode (SIMOPS) may easily last between 15 and 90 minutes, depending on jacking speed, operational water depth, and field procedures, on approach to the asset. The area of operation is close to the asset, which increases the risk of collision with the asset. Most of the studies on jack-up vessels focus on impact force acting on the leg during touchdown or penetrations, such as Elkadi et al. (2014) and Kreuzer et al. (2014).

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