scholarly journals Vertical hydrodynamic tube as a working tool in a shipbuilding experiment

2020 ◽  
Vol 4 (394) ◽  
pp. 53-62
Author(s):  
Andrey S. Guzeev
Keyword(s):  
Flow Visualization ◽  
Flow Pattern ◽  
Test Section ◽  
Ship Design ◽  
Engineering Structures ◽  
Early Stages ◽  
Marine Engineering ◽  
Technical Solutions ◽  
Bridge Spans

Object and purpose of research. The object of the research is the flow pattern around ship models and engineering structures. The purpose is to optimize their outer lines. Materials and methods. The studies were carried out in a vertical hydrodynamic tunnel with a transparent test section using flow visualization methods. Main results. After the series of studies, technical solutions have been developed and implemented on sea-going ships and marine engineering structures. The paper shows that these studies are strongly recommended at early stages of ship design, especially for the structures with flow separations, like funnels, helipads, upper decks, air inlets, bridge spans, etc. Conclusion. The results indicate that the vertical hydrodynamic tunnel can be successfully used for development of outer lines for hulls and other engineering structures with flow separations.

scholarly journals Studious Ship Design: A Review of UCL MSC Warship Designs

2019 ◽  
Author(s):  
R. J. Pawling ◽  
C. Savage
Keyword(s):  
Academic Staff ◽  
Ship Design ◽  
User Requirements ◽  
Naval Architecture ◽  
Marine Engineering ◽  
The Uk ◽  
Technical Solutions

It is more than 50 years since the UK MoD teaching of warship design moved from Greenwich to UCL, and the course has evolved into MSc Naval Architecture and MSc Marine Engineering courses covering both warships and other complex service vessels, with students from navies, governments and industry worldwide. This presentation will describe this years’ designs, outlining the technical solutions proposed to a diverse set of user requirements set by the academic staff. Some of the educational aspects and challenges of the design exercise course will also be described. Portions of this paper are reproduced from reference [1]; which provides a more detailed example of the work put into a typical MSc SDX ship design.

Characterization and Optimization of the Flow Pattern Inside a Diaphragm Blood Pump Based on Flow Visualization Techniques

ASAIO Journal ◽  
1998 ◽  
Vol 44 (5) ◽  
pp. M714-M718 ◽  
Author(s):  
Masako Nakata ◽  
Toru Masuzawa ◽  
Eisuke Tatsumi ◽  
Yoshiyuki Taenaka ◽  
Takashi Nishimura ◽  
...  
Keyword(s):  
Flow Visualization ◽  
Flow Pattern ◽  
Blood Pump ◽  
Visualization Techniques

Computer Representation of Numerical Expertise for Preliminary Ship Design

1989 ◽  
Vol 26 (04) ◽  
pp. 289-302
Author(s):  
A. H. B. Duffy ◽  
K. J. MacCallum
Keyword(s):  
Experimental System ◽  
Ship Design ◽  
Design Model ◽  
Design System ◽  
Early Stages ◽  
Worked Example ◽  
Preliminary Ship Design ◽  
Numerical Design ◽  
Computer Representation ◽  
Computer Based

In the early stages of ship design a considerable amount of experience and knowledge is used to build and evaluate empirical models with known design relationships. However, computer-based systems which aim to assist this stage have tended to concentrate on the analytical aspects of the process and have not been successful in integrating with this expertise and benefitting from it. This paper presents some of the results of a program of research into methods and representing knowledge of empirical numerical relationships used in these early stages of the design process. The work is based on an experimental system, DESIGNER, described in earlier papers. The DESIGNER system is used to carry out a series of evaluations of design sessions, using a warship design model. By examining the progress toward a set of design goals and the classes of interactions used, an improved understanding of the requirements of an interactive numerical design system is developed. As a consequence, methods have been developed to handle approximate values and relationships, to include design margins, and to represent explicitly in the system the definition and use of goals, or design requirements. Using a design model representing a bulk carrier, the paper then presents a worked example to illustrate the use of the new numerical knowledge techniques. It is concluded that the techniques could make a useful contribution to any interactive numerical design system which aims to provide improved use of expertise.

Numerically Modeling the Effect of Flexibility on Flow around Marine Engineering Structures: Using the Shape of the Saguaro Cactus

2020 ◽  
Vol 36 (3) ◽  
pp. 628
Author(s):  
Jianfeng Lin ◽  
Dagang Zhao ◽  
Chunyu Guo ◽  
Zuotian Zhang ◽  
Yumin Su
Keyword(s):  
Engineering Structures ◽  
Marine Engineering

scholarly journals Features of Earthquake-Induced Seabed Liquefaction and Mitigation Strategies of Novel Marine Structures

2020 ◽  
Vol 8 (5) ◽  
pp. 310 ◽  
Author(s):  
Yu Huang ◽  
Xu Han
Keyword(s):  
Mitigation Strategies ◽  
Marine Structures ◽  
Engineering Structures ◽  
Soil Layers ◽  
Seismic Liquefaction ◽  
Oil Platforms ◽  
Field Investigations ◽  
Marine Engineering ◽  
The Impact ◽  
Gas Component

With the accelerated development of marine engineering, a growing number of marine structures are being constructed (e.g., seabed pipelines, drilling platforms, oil platforms, wind turbines). However, seismic field investigations over recent decades have shown that many marine structures were damaged or destroyed due to liquefaction. Seismic liquefaction in marine engineering can have huge financial repercussions as well as a devastating effect on the marine environment, which merits our great attention. As the effects of seawater and the gas component in the seabed layers are not negligible, the seabed soil layers are more prone to liquefaction than onshore soil layers, and the liquefied area may be larger than when liquefaction occurs on land. To mitigate the impact of liquefaction events on marine engineering structures, some novel liquefaction-resistant marine structures have been proposed in recent years. This paper reviews the features of earthquake-induced liquefaction and the mitigation strategies for marine structures to meet the future requirements of marine engineering.

scholarly journals Direct Observation of Filling Process and Porosity Prediction in High Pressure Die Casting

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1099 ◽  
Author(s):  
Hanxue Cao ◽  
Chao Shen ◽  
Chengcheng Wang ◽  
Hui Xu ◽  
Juanjuan Zhu
Keyword(s):  
Numerical Simulation ◽  
High Pressure ◽  
Flow Visualization ◽  
Flow Pattern ◽  
Experimental Verification ◽  
Die Casting ◽  
Filling Process ◽  
High Pressure Die Casting ◽  
Visualization Experiment ◽  
Pressure Die Casting

Although numerical simulation accuracy makes progress rapidly, it is in an insufficient phase because of complicated phenomena of the filling process and difficulty of experimental verification in high pressure die casting (HPDC), especially in thin-wall complex die-castings. Therefore, in this paper, a flow visualization experiment is conducted, and the porosity at different locations is predicted under three different fast shot velocities. The differences in flow pattern between the actual filling process and the numerical simulation are compared. It shows that the flow visualization experiment can directly observe the actual and real-time filling process and could be an effective experimental verification method for the accuracy of the flow simulation model in HPDC. Moreover, significant differences start to appear in the flow pattern between the actual experiment and the Anycasting solution after the fragment or atomization formation. Finally, the fast shot velocity would determine the position at which the back flow meets the incoming flow. The junction of two streams of fluid would create more porosity than the other location. There is a transition in flow patterns due to drag crisis under high fast shot velocity around two staggered cylinders, which resulted in the porosity relationship also changing from R1 < R3 < R2 (0.88 m/s) to R1 < R2 < R3 (1.59 and 2.34 m/s).

Flow Visualization Study of Jet and Bucket Interactions in Traditional and Hooped Pelton Runner

2019 ◽  
Author(s):  
Gaurangkumar Chaudhari ◽  
Salim Channiwala ◽  
Samip Shah ◽  
Digvijay Kulshreshtha
Keyword(s):  
Flow Visualization ◽  
Flow Pattern ◽  
High Speed ◽  
Early Stage ◽  
Small Scale ◽  
High Speed Photography ◽  
Pelton Turbine ◽  
Single Jet ◽  
Absolute Frame ◽  
First Time

Abstract This paper aims to study the flow pattern in and around a bucket of a Traditional and a Hooped Pelton runner at single injector operation and illustrates different stages of jet interaction. High speed photography is used to study the flow pattern, keeping the camera in different positions relative to the jet and to the bucket. It is concluded from the results that the flow visualization study, provides exceptional observations with an absolute frame of reference to mark the bucket duty period of a single-jet Pelton runner. The small scale models display erosion damages at the bucket lips, this indicated that the high pressure occur in the early stage of interaction. This fact is substantiated by the present flow visualization studies for the first time. The uncertainty of the free surface outflow within the Pelton turbine bucket establishes good documentation. The results are helpful to know the interaction between the jet and bucket of Pelton turbine.

An Experimental Study on Air-Water Two-Phase Flow Patterns in Pebble Beds

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Bai Bofeng ◽  
Liu Maolong ◽  
Su Wang ◽  
Zhang Xiaojie
Keyword(s):  
Experimental Study ◽  
Flow Pattern ◽  
Test Section ◽  
Slug Flow ◽  
Annular Flow ◽  
Two Phase Flow ◽  
Flow Patterns ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Pattern Transition

An experimental study was conducted on the air-water two-phase flow patterns in the bed of rectangular cross sections containing spheres of regular distribution. Three kinds of glass spheres with different diameters (3 mm, 6 mm, and 8 mm) were used for the establishment of the test section. By means of visual observations of the two-phase flow through the test section, it was discovered that five different flow patterns occurred within the experimental parameter ranges, namely, bubbly flow, bubbly-slug flow, slug flow, slug-annular flow, and annular flow. A correlation for the bubble and slug diameter in the packed beds was proposed, which was an extended expression of the Tung/Dhir model, Jamialahmadi’s model, and Schmidt’s model. Three correlations were proposed to calculate the void friction of the flow pattern transition in bubble flow, slug flow, and annular flow based on the bubble model in the pore region. The experimental result showed that the modified Tung and Dhir model of the flow pattern transition was in better agreement with the experimental data compared with Tung and Dhir’s model.

Flow Pattern, Void Fraction and Pressure Drop During Adiabatic Two-Phase Gas-Liquid Flow in Vertical Micro-Channel

2012 ◽  
Author(s):  
Sira Saisorn ◽  
Somchai Wongwises
Keyword(s):  
Pressure Drop ◽  
Flow Pattern ◽  
Void Fraction ◽  
Test Section ◽  
Annular Flow ◽  
Fused Silica ◽  
Working Fluid ◽  
Micro Channel ◽  
Two Phase ◽  
Churn Flow

The experimental investigation is performed to study two-phase flow pattern, void fraction and pressure drop characteristics in a vertical micro-channel. The test section is a fused silica tube with a diameter of 0.53 mm and a length of 320 mm. Air and water are used as working fluid which is introduced to the test section in vertical upward direction. The test runs are done at superficial velocities of gas and liquid ranging respectively from 0.375 to 21.187 m/s and 0.004 to 2.436 m/s. Stereozoom microscope mounted together with camera are employed to conduct flow visualization from which slug flow, throat-annular flow, churn flow, annular flow and annular-rivulet flow are observed. Based on image analysis, void fraction data are obtained and found to be linear relationship with volumetric quality. The frictional pressure drop is relatively high when the formation of churn flow is established. Besides, the two-phase frictional multiplier is found to be strongly dependent on both mass flux and flow pattern.

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