Straight-ahead self-propulsion and turning maneuvers of DTC container ship with direct CFD simulations

2022 ◽  
Vol 244 ◽  
pp. 110381
Author(s):  
Omer Kemal Kinaci ◽  
Deniz Ozturk
Author(s):  
Sopheak Seng ◽  
Jørgen Juncher Jensen

A study of slamming events in conditional waves is presented in this paper. The ship is sailing in head sea and the motion is solved for under the assumption of rigid body motion constrained to two degree-of-freedom i.e. heave and pitch. Based on a time domain non-linear strip theory most probable conditional waves are generated to induce short term extreme responses of 4500 MNm sagging and hogging vertical bending moment (VBM) amidships on a modern 9,400-TEU post-Panamax container ship and 3000 MNm (sag) on a Panamax container ship. The results of the strip theory are compared to the results of free surface NS/VOF CFD simulations under the same wave conditions. In moderate seas and no occurrence of slamming the structural responses predicted by the methods agree well. When slamming occurs the strip theory overpredicts VBM but the peak values of VBM occurs at approximately the same time as predicted by the CFD method implying the possibility to use the more accurate CFD results to improve the estimation of slamming loads in the strip theory through a rational correction coefficient.


2013 ◽  
Vol 9 (2) ◽  
pp. 173-186 ◽  
Author(s):  
Mari Wiklund

Asperger syndrome (AS) is a form of high-functioning autism characterized by qualitative impairment in social interaction. People afflicted with AS typically have abnormal nonverbal behaviors which are often manifested by avoiding eye contact. Gaze constitutes an important interactional resource, and an AS person’s tendency to avoid eye contact may affect the fluidity of conversations and cause misunderstandings. For this reason, it is important to know the precise ways in which this avoidance is done, and in what ways it affects the interaction. The objective of this article is to describe the gaze behavior of preadolescent AS children in institutional multiparty conversations. Methodologically, the study is based on conversation analysis and a multimodal study of interaction. The findings show that three main patterns are used for avoiding eye contact: 1) fixing one’s gaze straight ahead; 2) letting one’s gaze wander around; and 3) looking at one’s own hands when speaking. The informants of this study do not look at the interlocutors at all in the beginning or the middle of their turn. However, sometimes they turn to look at the interlocutors at the end of their turn. This proves that these children are able to use gaze as a source of feedback. When listening, looking at the speaker also seems to be easier for them than looking at the listeners when speaking.


2020 ◽  
Vol 20 (3) ◽  
pp. 343-353
Author(s):  
Ngo Van He ◽  
Le Thi Thai

In this paper, a commercial CFD code, ANSYS-Fluent has been used to investigate the effect of mesh number generated in the computed domain on the CFD aerodynamic performances of a container ship. A full-scale model of the 1200TEU container ship has been chosen as a reference model in the computation. Five different mesh numbers for the same dimension domain have been used and the CFD aerodynamic performances of the above water surface hull of the ship have been shown. The obtained CFD results show a remarkable effect of mesh number on aerodynamic performances of the ship and the mesh convergence has been found. The study is an evidence to prove that the mesh number has affected the CFD results in general and the accuracy of the CFD aerodynamic performances in particular.


2012 ◽  
Vol 81 (6) ◽  
pp. 485-488
Author(s):  
Masanobu TOYODA ◽  
Tsunehisa HANDA

Author(s):  
Dilesh Maharjan ◽  
Mustafa Hadj-Nacer ◽  
Miles Greiner ◽  
Stefan K. Stefanov

During vacuum drying of used nuclear fuel (UNF) canisters, helium pressure is reduced to as low as 67 Pa to promote evaporation and removal of remaining water after draining process. At such low pressure, and considering the dimensions of the system, helium is mildly rarefied, which induces a thermal-resistance temperature-jump at gas–solid interfaces that contributes to the increase of cladding temperature. It is important to maintain the temperature of the cladding below roughly 400 °C to avoid radial hydride formation, which may cause cladding embrittlement during transportation and long-term storage. Direct Simulation Monte Carlo (DSMC) method is an accurate method to predict heat transfer and temperature under rarefied condition. However, it is not convenient for complex geometry like a UNF canister. Computational Fluid Dynamics (CFD) simulations are more convenient to apply but their accuracy for rarefied condition are not well established. This work seeks to validate the use of CFD simulations to model heat transfer through rarefied gas in simple two-dimensional geometry by comparing the results to the more accurate DSMC method. The geometry consists of a circular fuel rod centered inside a square cross-section enclosure filled with rarefied helium. The validated CFD model will be used later to accurately estimate the temperature of an UNF canister subjected to vacuum drying condition.


Particuology ◽  
2019 ◽  
Vol 47 ◽  
pp. 63-69
Author(s):  
Shuai Yang ◽  
Xiangdi Zhao ◽  
Wanfu Sun ◽  
Jiwu Yuan ◽  
Zheng Wang

Sign in / Sign up

Export Citation Format

Share Document