scholarly journals Large-scale and drift-free surface reconstruction using online subvolume registration

Author(s):  
Nicola Fioraio ◽  
Jonathan Taylor ◽  
Andrew Fitzgibbon ◽  
Luigi Di Stefano ◽  
Shahram Izadi
2016 ◽  
Author(s):  
Janek Meyer ◽  
Hannes Renzsch ◽  
Kai Graf ◽  
Thomas Slawig

While plain vanilla OpenFOAM has strong capabilities with regards to quite a few typical CFD-tasks, some problems actually require additional bespoke solvers and numerics for efficient computation of high-quality results. One of the fields requiring these additions is the computation of large-scale free-surface flows as found e.g. in naval architecture. This holds especially for the flow around typical modern yacht hulls, often planing, sometimes with surface-piercing appendages. Particular challenges include, but are not limited to, breaking waves, sharpness of interface, numerical ventilation (aka streaking) and a wide range of flow phenomenon scales. A new OF-based application including newly implemented discretization schemes, gradient computation and rigid body motion computation is described. In the following the new code will be validated against published experimental data; the effect on accuracy, computational time and solver stability will be shown by comparison to standard OF-solvers (interFoam / interDyMFoam) and Star CCM+. The code’s capabilities to simulate complex “real-world” flows are shown on a well-known racing yacht design.


2021 ◽  
Vol 3 (10) ◽  
Author(s):  
Anna Samoilova ◽  
Alexander Nepomnyashchy

Abstract A novel type of Marangoni convection was predicted theoretically a decade ago. The thin liquid film atop a substrate of low thermal conductivity was considered. In the case of heating from below, the Marangoni convection emerges not only in a conventional stationary regime, but also as oscillatory flows. Specifically, the oscillatory Marangoni convection emerges if (1) the heat flux from the free surface is small, and (2) the large-scale deformation of the free surface is allowed. During the past decade, this novel Marangoni convection was detected and investigated in several other theoretical works. The review discusses the recent achievements in studying the oscillatory Marangoni convection in a thin film heated from below. The guiding data for observation of the oscillatory regime are also provided.


Author(s):  
M.A. Moskalenko ◽  
T.E. Malikova ◽  
S.M. Zatepyakin ◽  
I.B. Druz

Морская отрасль является важнейшим звеном в международной торговле, так как морские суда представляют собой наиболее рентабельный способ доставки больших партий массовых грузов на значительные расстояния. Современная логистика перевозок массовых навалочных грузов идет по пути увеличения судовых партий и как следствие, за счет экономии издержек на эффекте масштаба последние годы произошел существенный рост размеров универсальных судов. На универсальных судах, за счет роста торговли продовольствием и сужения фрахтового рынка, в последние годы стали активно перевозиться зерновые навалочные грузы. Известно, что смещение навалочных грузов было связано с большими рисками опрокидывания от потери остойчивости для балкеров, где от потери остойчивости происходит более 46 процентов всех серьезных аварийных случаев. Проблема обеспечения остойчивости становится еще более актуальной при перевозке зерновых навалочных грузов, имеющих усадку примерно в два процента от своего объема, за счет чего во время рейса всегда образуются пустоты в трюмах между свободной поверхностью груза и палубой. Предполагается, что при максимально возможном смещении зерна его свободная поверхность образует с горизонталью углы в 15 и 25 градусов для заполненных и соответственно незаполненных отсеков. Для универсальных судов риски потери остойчивости от смещения груза при перевозках зерна, за счет масштабного эффекта большой удельной погрузочной кубатуры трюмов и высоты борта возрастают многократно.The Maritime industry is an important link in international trade because sea vessels are the most cost-effective way to deliver large quantities of bulk cargo over long distances. Modern transportation of cargo in bulk is on the path of increasing of shiploads and as a result, due to effective on scale effect, there has been a significant increase in the size of universal vessels in recent years. Grain bulk cargo has been actively transported on universal vessels in recent years due to the growth of food trade and the segmentation of the freight market. It is known fact that the displacement of bulk cargo in the vessel holds was associated with high risks of overturning from loss of stability for bulk carriers. More than 46 percent of all serious accidents occur from loss of stability. The problem of ensuring stability becomes even more urgent when transporting grain bulk cargo, which has a shrinkage of about two percent of its volume, which is a reason of free surface between the cargo and the deck inside of vessel holds. It is assumed that at the maximum possible displacement of the grain, its free surface forms angles of 15 and 25 degrees with the horizontal for filled and unfilled compartments, respectively. For multipurpose universal vessels, the risks of loss of stability during grain transportation due to cargo displacement and because of the large-scale effect of the large loading cubic capacity of the holds and the height of the side, increase many times.


Author(s):  
Thomas Wiemann ◽  
Marcel Mrozinski ◽  
Dominik Feldschnieders ◽  
Kai Lingemann ◽  
Joachim Hertzberg

2019 ◽  
Vol 6 (12) ◽  
pp. 3560-3578 ◽  
Author(s):  
Mengjuan Zhou ◽  
Mengzhen Fang ◽  
Zhenzhen Quan ◽  
Hongnan Zhang ◽  
Xiaohong Qin ◽  
...  

Micro-gradient structured PAN sub-micro fibrous membrane with high-efficiency air purification performance was fabricated via one-step free surface electrospinning with large-scale yield, firstly demonstrated as air filters.


Author(s):  
Fumio Shimizu ◽  
Kiyoshi Hatakenaka ◽  
Kazuhiro Tanaka ◽  
Hiroshi Shigefuji ◽  
Takeshi Shimizu

A siphon phenomenon is one of gas/liquid two-phase flows including free surface deformation. Since the large-scale deformation of the free surface causes a loud noise, it is important to investigate the motion of the free surface. The purpose of the present study is to reproduce a siphon phenomenon in computer, and to analyze an internal flow field of the siphon phenomenon. An oscillating flow in two-dimensional U-tube was simulated to verify our computational codes, and good agreement compared with the theoretical period was obtained. After that, the numerical reproduction of a siphon phenomenon was succeeded and the behavior of the free surface was captured reasonably.


Sign in / Sign up

Export Citation Format

Share Document