Sensitivity Analysis in Parametric Rolling of a Modern Cruise Ship Using Numerical Simulations in 6-Dof

2021 ◽  
Author(s):  
Bulent Duz
Keyword(s):  
Sensitivity Analysis ◽  
Numerical Simulations ◽  
Cruise Ship ◽  
Parametric Rolling

Sensitivity Analysis in Parametric Rolling of a Modern Cruise Ship Using Numerical Simulations in 6-DOF

2020 ◽  
Author(s):  
Bülent Düz
Keyword(s):  
Sensitivity Analysis ◽  
Numerical Simulations ◽  
Time Domain ◽  
Nonlinear Phenomenon ◽  
Cruise Ship ◽  
Parametric Roll ◽  
Parametric Rolling ◽  
Maximum Angle ◽  
Strip Theory ◽  
The Time Domain

Abstract Parametric roll is a nonlinear phenomenon that can result in large roll angles coupled with significant pitch motions. These motions might induce large loads on the ship structure, and compromise the safety of the crew and the cargo. The severity of the motions might reach to such levels that capsizing might occur. In this study sensitivity analysis in parametric rolling of a modern cruise ship is investigated using numerical simulations. Several parameters were considered as sources of uncertainty such as the combined effect of GM and roll radius of gyration, roll damping, ship speed, and fin characteristics. In terms of fin characteristics, fin angle rate and maximum angle, fin area and aspect ratio, and fin gains were investigated. Additionally, the non-ergodicity of parametric roll was studied as well as the effect of simulation duration on the statistics of parametric roll. The simulations were carried out with a hybrid time-domain seakeeping and manoeuvring code. The time-domain code was used in combination with a strip-theory based frequency-domain program in order to calculate diffraction and radiation forces as well as added-mass. The time-domain code was able simulate the dynamic behavior of a steered ship in 6-DOF, where the motions can be large up to the moment of capsize.

scholarly journals A Stochastic Harmonic Oscillator Temperature Model for the Valuation of Weather Derivatives

Mathematics ◽  
2021 ◽  
Vol 9 (22) ◽  
pp. 2890
Author(s):  
Alessio Giorgini ◽  
Rogemar S. Mamon ◽  
Marianito R. Rodrigo
Keyword(s):  
Sensitivity Analysis ◽  
Parameter Estimation ◽  
Harmonic Oscillator ◽  
Numerical Simulations ◽  
Model Parameters ◽  
Call Option ◽  
Temperature Model ◽  
Option Prices ◽  
Harmonic Oscillator Model ◽  
Temperature Dynamics

Stochastic processes are employed in this paper to capture the evolution of daily mean temperatures, with the goal of pricing temperature-based weather options. A stochastic harmonic oscillator model is proposed for the temperature dynamics and results of numerical simulations and parameter estimation are presented. The temperature model is used to price a one-month call option and a sensitivity analysis is undertaken to examine how call option prices are affected when the model parameters are varied.

Assessing the impact of agrochemicals on schistosomiasis transmission: A mathematical study

2021 ◽  
pp. 2150049
Author(s):  
Liming Cai ◽  
Peixia Yue ◽  
Mini Ghosh ◽  
Xuezhi Li
Keyword(s):  
Mathematical Model ◽  
Sensitivity Analysis ◽  
Numerical Simulations ◽  
Disease Transmission ◽  
Agricultural Pollution ◽  
Parasitic Disease ◽  
Mathematical Study ◽  
Proposed Model ◽  
Existence And Stability ◽  
The Impact

Schistosomiasis is a snail-borne parasitic disease, which is affecting almost 240 million people worldwide. The number of humans affected by schistosomiasis is continuously increasing with the rise in the use of agrochemicals. In this paper, a mathematical model is formulated and analyzed to assess the effect of agrochemicals on the transmission of schistosomiasis. The proposed model incorporates the effects of fertilizers, herbicides and insecticides on susceptible snails and snail predators along with schistosomiasis disease transmission. The existence and stability of the equilibria in the model are discussed. Sensitivity analysis is performed to identify the key parameters of the proposed model, which contributes most in the transmission of this disease. Numerical simulations are also performed to assess the impact of fertilizers, herbicides and insecticides on schistosomiasis outbreaks. Our study reveals that the agricultural pollution can enhance the transmission intensity of schistosomiasis, and in order to prevent the outbreak of schistosomiasis, the use of pesticides should be controlled.

scholarly journals Assessment of CFD Solvers and Turbulent Models for Water Free Jets in Spillways

Fluids ◽  
2020 ◽  
Vol 5 (3) ◽  
pp. 104
Author(s):  
António Muralha ◽  
José F. Melo ◽  
Helena M. Ramos
Keyword(s):  
Experimental Data ◽  
Sensitivity Analysis ◽  
Velocity Field ◽  
Numerical Simulations ◽  
Free Water ◽  
Concentration Profiles ◽  
Air Concentration ◽  
Free Jets ◽  
Free Jet ◽  
Turbulent Models

The capability of two different OpenFOAM® solvers, namely interFoam and twoPhaseEulerFoam, in reproducing the behavior of a free water jet was investigated. Numerical simulations were performed in order to obtain the velocity and air concentration profiles along the jet. The turbulence intensity was also analyzed. The obtained results were compared with published experimental data and, in general, similar velocity and air concentration profiles were found. InterFoam solver is able to reproduce the velocity field of the free jet but has limitations in the simulation of the air concentration. TwoPhaseEulerFoam performs better in reproducing the air concentration along the jet, the results being in agreement with the experimental data, although the computational runs are less stable and more time consuming. The sensitivity analysis of the inlet turbulent intensity showed that it has no influence in the characteristics of the jet core. With this research it is possible to conclude that: interFoam with k-Epsilon (k-ε) turbulence model is the best choice if the goal of the numerical simulations is the simulation of the velocity field of the jet. Meanwhile, twoPhaseEulerFoam with mixturek-Epsilon (mk-ε) shall be considered if the objective is the simulation of the velocity field and the air concentration.

Sensitivity Analysis of Vibration Suppression Based on the Multiple-Mode Negative Impulses Input Shapers

2012 ◽  
Vol 189 ◽  
pp. 312-316
Author(s):  
Yue Zhan Wang ◽  
Qi Bo Yan ◽  
Bing Li ◽  
Yu Lan Wei
Keyword(s):  
Sensitivity Analysis ◽  
Numerical Simulations ◽  
Delay Time ◽  
Parallel Manipulator ◽  
Vibration Suppression ◽  
System Response ◽  
Input Shaping ◽  
Residual Vibration ◽  
Multiple Mode

The structure of a 3-DOF parallel manipulator is presented. The methodologies of multiple-mode negative impulses input shaping is introduced, which can decrease the delay time of the system response while the residual vibration is suppressed. The parameters of two-mode negative impulses and positive impulses input shapers of the 3-DOF manipulator are presented. The sensitivity analysis of these input shapers are carried out through numerical simulations, and the robust of the input shapers are presented and compared.

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