Numerical Simulation of the “Floating Spiral” Pipeline Installation Procedure: Second Stage, Spiral Transportation, Behavior Under Waves

2008 ◽  
Author(s):  
Bruno Martins Jacovazzo ◽  
Fabri´cio Nogueira Correˆa ◽  
Carl Horst Albrecht ◽  
Breno Pinheiro Jacob ◽  
Fernando Gomes da Silva Torres ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Optimal Control ◽  
Environmental Conditions ◽  
Companion Paper ◽  
Time Constraints ◽  
Second Stage ◽  
Parametric Studies ◽  
Large Length ◽  
Transportation Behavior ◽  
Flat Spiral

The Floating Spiral pipeline installation method consists basically in winding the pipeline into a huge floating spiral, and towing this assembly to the installation site, where the spiral is then unwound and lowered to the seabed. In this method the pipeline is fabricated onshore, as the spiral is created, under well controlled conditions and relatively relaxed time constraints. Therefore the welds can be better inspected, which allows for optimal control of quality in pipeline manufacturing. The first stage of the installation process by this method consists in setting the pipeline afloat and winding it elastically to form a large flat spiral. This stage is studied in a companion paper [1], to be also presented at IPC2008. The second stage consists in towing the floating spiral pipeline employing standard tugboats before laying it at the installation site. The objective of this work is, therefore, to present results of parametric studies for a large length pipeline at this second stage of the Floating Spiral method. The focus now is in the pipeline behavior under wave environmental conditions during transportation. Several numerical simulations are performed and the results are discussed and compared.

Numerical Simulation of the ‘Floating Spiral’ Pipeline Installation Procedure: First Stage, Spiral Assembly

2008 ◽  
Author(s):  
Danilo Machado Lawinscky da Silva ◽  
Mauro Henrique Alves de Lima ◽  
Carl Horst Albrecht ◽  
Breno Pinheiro Jacob ◽  
Fernando Gomes de Silva Torres ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Optimal Control ◽  
Numerical Simulations ◽  
Companion Paper ◽  
Single Operation ◽  
Flat Spiral ◽  
Fixed Structure

The underlying concept for the Floating Spiral pipeline installation method is to wind the pipeline into a huge floating spiral, and then tow this assembly to the installation site, where the spiral is then unwound and lowered to the seabed in a single operation. In this method the pipes are fabricated on shore, which allows for optimal control of costs and quality in pipeline manufacturing. The first stage of the installation process by this method consists in setting the pipeline afloat and winding it elastically to form a large flat spiral, which is then ready to be towed to the installation site by standard tugboats. The objective of this work is to present results of studies for a long pipeline length at this first stage of the Floating Spiral method. The focus here is the process of moving the pipeline around a fixed structure to wind it and form the floating spiral. Problems related to modeling of contact between pipeline and its guides at the first spiral cycle, as well as contact between further pipeline cycles, are rigorously analyzed. Several numerical simulations are performed; the results are presented and discussed. Other stages of this installation method have also been studied, and are presented in a companion paper [1].

scholarly journals Numerical Simulation Study of Booming Effect in Fast Currents of Inland River

2018 ◽  
Vol 38 ◽  
pp. 03048
Author(s):  
Rongchang Chen ◽  
Chen Liu ◽  
Xiaofeng Luo ◽  
Wei Shen
Keyword(s):  
Numerical Simulation ◽  
Environmental Conditions ◽  
Yangtze River ◽  
Flood Control ◽  
Peak Flow ◽  
Control Design ◽  
Simulation Method ◽  
Design Flow ◽  
The Yangtze River ◽  
Annual Average

In the downstream tidal section of the Yangtze River, nine kinds of combinations of hydrological environmental conditions are considered, including the annual average runoff flow, the annual average peak flow and the flood control design flow, as well as the three conditions of spring, medium and neap tides. By means of the numerical simulation method, the effective performance parameter values for conventional intercepting boom under different environmental conditions are obtained by simulating 9 kinds of maximum current speed to withstand, Max.CS, respectively. The results show that, in the downstream fast current tidal section of the Yangtze River, for the boom performance index of Max.CS, the relatively extensive applicability value should be 3.0kn under the condition of the annual average runoff flow; 4.0Kn should be selected under the condition of the annual average peak flow; and 4.5Kn should be selected under the flood control design flow. This study can provide technical support for the design, selection and use of booms in downstream waters of the Yangtze River.

scholarly journals Analysis of Atangana–Baleanu fractional-order SEAIR epidemic model with optimal control

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Chernet Tuge Deressa ◽  
Gemechis File Duressa
Keyword(s):  
Numerical Simulation ◽  
Optimal Control ◽  
Fractional Order ◽  
Control Strategy ◽  
Epidemic Model ◽  
Numerical Scheme ◽  
Order Derivative ◽  
Control Analysis ◽  
Fractional Order Derivative ◽  
Fractional Orders

AbstractWe consider a SEAIR epidemic model with Atangana–Baleanu fractional-order derivative. We approximate the solution of the model using the numerical scheme developed by Toufic and Atangana. The numerical simulation corresponding to several fractional orders shows that, as the fractional order reduces from 1, the spread of the endemic grows slower. Optimal control analysis and simulation show that the control strategy designed is operative in reducing the number of cases in different compartments. Moreover, simulating the optimal profile revealed that reducing the fractional-order from 1 leads to the need for quick starting of the application of the designed control strategy at the maximum possible level and maintaining it for the majority of the period of the pandemic.

scholarly journals An Investigation of Dynamic Responses and Head Injuries of Standing Subway Passengers during Collisions

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Yong Peng ◽  
Tuo Xu ◽  
Lin Hou ◽  
Chaojie Fan ◽  
Wei Zhou
Keyword(s):  
Numerical Simulation ◽  
Head Injury ◽  
Head Injuries ◽  
Dynamic Responses ◽  
Passive Safety ◽  
Friction Coefficients ◽  
Safety Design ◽  
Parametric Studies ◽  
Simulation Results ◽  
Set Up

With the development of the subway and the pressing demand of environmentally friendly transportation, more and more people travel by subway. In recent decades, the issues about passenger passive safety on the train have received extensive attention. In this research, the head injury of a standing passenger in the subway is investigated. Three MADYMO models of the different standing passenger postures, defined as baseline scenarios, are numerically set up. HIC15values of passengers with different postures are gained by systematic parametric studies. The injury numerical simulation results of various scenarios with different friction coefficients, collision acceleration, standing angle, horizontal handrail height, and ring handrail height are analyzed. Results show that the horizontal handrail provides better protection in the three different standing passenger postures. Different friction coefficients and the standing angle have great impact on the head injuries of passengers in three different scenarios. The handrail height also has some effects on head injury of passengers with different standing postures, so it is necessary to be considered when designing the interior layout of the subway. This study may provide guidance for the safety design of the subway and some advices for standing subway passengers.

Dynamic model for population distribution and optimum immigration and job creation policies

2004 ◽  
Vol 31 (2) ◽  
pp. 261
Author(s):  
N. U. Ahmed ◽  
Yongjuan He
Keyword(s):  
Numerical Simulation ◽  
Optimal Control ◽  
Control Theory ◽  
Dynamic Model ◽  
Optimal Control Theory ◽  
Close Agreement ◽  
Population Distribution ◽  
Job Creation ◽  
Population Level ◽  
Decision Control

In this paper we demonstrate that by use of modern Systems and Optimal Control theory, it is possible to formulate optimum immigration and job creation strategies while maintaining population level close to certain pre-specified targets. With this objective in mind, we consider a simplified dynamic model based on a previous model developed in (Ahmed and Rahim, 2001:325-358) to describe the population distribution in Canada. Numerical results demonstrate that the model population is in close agreement with the actual population. This model was then used to formulate a control problem with immigration and job creation rates being the decision (control) variables. Using optimal control theory, optimum immigration and job creation policies were determined. Results are illustrated by numerical simulation and they are found to be very encouraging.

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