Several remarks on EFD and CFD for ship roll decay

Hashimoto, Hirotada; Omura, Tomoyuki; Matsuda, Akihiko; Yoneda, Shota; Stern, Frederick; Tahara, Yusuke

doi:10.1016/j.oceaneng.2019.05.064

Cited by 11 publications

(2 citation statements)

References 7 publications

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“…This method has known shortcomings, but it is the best method available. More recently, CFD has been used to estimate the roll damping, and this method has been shown to give good results [14]. It is noted here that an inaccurate estimation of the roll damping dominates the results from further simulations on most of the stability failure modes defined by the IMO.…”

Section: Introductionmentioning

confidence: 89%

A Comparison of Numerical Simulations and Model Experiments on Parametric Roll in Irregular Seas

Kapsenberg

Wandji

Düz

et al. 2020

JMSE

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The recently finalised Second Generation Intact Stability Criteria (SGISC), produced by the International Maritime Organisation (IMO), contain a level 3 assessment, the so-called Direct Stability Assessment (DSA). This assessment can be carried out using either model experiments or simulations. The fact that such a choice is given implies that the methods are equivalent in accuracy. This assumption has been verified, for one case, by the Cooperative Research Ships (CRS) community. The verification was based on new model experiments and calculated results, using four different programs owned by different CRS members. Results of the verification of the parametric roll failure mode in regular waves were published before, but this study concerns results in irregular seas. The experimental and numerical results are compared in both probabilistic and deterministic manners. The probabilistic comparison showed that the simulation programs considered are sometimes conservative and sometimes non-conservative in the prediction of the probability of an extreme value. The deterministic comparison in head seas showed that parametric roll events were predicted in the simulations in a wave train that showed no sign of important roll events in the measurement. The deterministic comparison in the following seas, on the other hand, showed an accurate fit of experimental and numerical results. It is suggested that predictions could possibly be improved by adding non-linear diffraction forces to the numerical model.

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Section: Introductionmentioning

confidence: 89%

A Comparison of Numerical Simulations and Model Experiments on Parametric Roll in Irregular Seas

Kapsenberg

Wandji

Düz

et al. 2020

JMSE

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show abstract

“…The mathematical model of roll motion is established according to ship hydrodynamics, and the damping coefficients in the mathematical model are obtained by means of model tests or CFD simulations. Hashimoto et al [2] and Kianejad et al [3] forecasted the roll motion by the motion model with the obtained damping coefficients. In order to predict the ship roll motion, Kianejad et al [4] used the CFD method to calculate the damping coefficients; Liu et al [5] used CFD to predict the parametric roll characteristics; and Chen et al [6] used the CFD method to establish a numerical model of ship motion coupled with fluid motion.…”

Section: Introductionmentioning

confidence: 99%

Short-Term Prediction of Ship Roll Motion in Waves Based on Convolutional Neural Network

Hou,

Xia

2024

JMSE

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In this study, a short-term prediction method for ship roll motion in waves based on convolutional neural network (CNN) is presented. Firstly, based on the ship roll motion equation, the data for free roll attenuation motion in still water, roll motion in regular waves, and roll motion excited by irregular waves are simulated, respectively. Secondly, the simulation data is normalized and preprocessed, and then the time-sliding window technique is applied to construct the training and testing sample sets. Thirdly, the CNN model is trained by learning from the constructed training sample sets, and the well-trained CNN model is applied to predict the roll motion. To validate the CNN model’s prediction accuracy and effectiveness, a comparison between the forecasted results and the simulation data is conducted. Meanwhile, the predicted results are also compared with that of the long-short-term memory (LSTM) neural network. The research results demonstrate that CNN can effectively achieve accurate prediction of ship roll motion in waves, and its prediction accuracy is the same as that of the LSTM neural network.

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Estimation of ship roll damping and natural frequency using an extended Kalman filter applied to URANS output

Ozdemir

2023

Sādhanā

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Several remarks on EFD and CFD for ship roll decay

Cited by 11 publications

References 7 publications

A Comparison of Numerical Simulations and Model Experiments on Parametric Roll in Irregular Seas

A Comparison of Numerical Simulations and Model Experiments on Parametric Roll in Irregular Seas

Short-Term Prediction of Ship Roll Motion in Waves Based on Convolutional Neural Network

Estimation of ship roll damping and natural frequency using an extended Kalman filter applied to URANS output

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