Structural Stability of Three-Dimensional Vortex Flows

1985 ◽  
pp. 81-102 ◽  
Author(s):  
U. Dallmann
Keyword(s):  
Structural Stability ◽  
Three Dimensional ◽  
Vortex Flows

Accelerating ion diffusion with unique three-dimensionally interconnected nanopores for self-membrane high-performance pseudocapacitors

Nanoscale ◽  
2017 ◽  
Vol 9 (46) ◽  
pp. 18311-18317 ◽  
Author(s):  
Yuan Gao ◽  
Yuanjing Lin ◽  
Zehua Peng ◽  
Qingfeng Zhou ◽  
Zhiyong Fan
Keyword(s):  
Aspect Ratio ◽  
Surface Area ◽  
Structural Stability ◽  
High Aspect Ratio ◽  
High Performance ◽  
Three Dimensional ◽  
Rate Capability ◽  
Large Surface Area ◽  
Nanoporous Structure ◽  
Ion Diffusion

Three-dimensional interconnected nanoporous structure (3-D INPOS) possesses high aspect ratio, large surface area, as well as good structural stability. Profiting from its unique interconnected architecture, the 3-D INPOS pseudocapacitor achieves a largely enhanced capacitance and rate capability.

scholarly journals Strong and Reversible Adhesion of Interlocked 3D-Microarchitectures

Coatings ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 48 ◽  
Author(s):  
Minho Seong ◽  
Hyun-Ha Park ◽  
Insol Hwang ◽  
Hoon Eui Jeong
Keyword(s):  
Aspect Ratio ◽  
Structural Stability ◽  
High Aspect Ratio ◽  
Three Dimensional ◽  
Normal Direction ◽  
One Dimensional ◽  
Reversible Adhesion ◽  
Adhesion Behavior ◽  
Organic Nanomaterials ◽  
Good Agreement

Diverse physical interlocking devices have recently been developed based on one-dimensional (1D), high-aspect-ratio inorganic and organic nanomaterials. Although these 1D nanomaterial-based interlocking devices can provide reliable and repeatable shear adhesion, their adhesion in the normal direction is typically very weak. In addition, the high-aspect-ratio, slender structures are mechanically less durable. In this study, we demonstrate a highly flexible and robust interlocking system that exhibits strong and reversible adhesion based on physical interlocking between three-dimensional (3D) microscale architectures. The 3D microstructures have protruding tips on their cylindrical stems, which enable tight mechanical binding between the microstructures. Based on the unique 3D architectures, the interlocking adhesives exhibit remarkable adhesion strengths in both the normal and shear directions. In addition, their adhesion is highly reversible due to the robust mechanical and structural stability of the microstructures. An analytical model is proposed to explain the measured adhesion behavior, which is in good agreement with the experimental results.

Study on the structural stability evaluation of umbilical winch for ROV LARS

2018 ◽  
Vol 35 (1) ◽  
pp. 202-210
Author(s):  
Namsub Woo ◽  
Sangmok Han ◽  
Youngju Kim ◽  
Sunchul Huh ◽  
Hyunji Kim
Keyword(s):  
Structural Analysis ◽  
Dynamic Simulation ◽  
Structural Stability ◽  
Three Dimensional ◽  
High Technology ◽  
Design Methods ◽  
Stability Evaluation ◽  
Content Type ◽  
Dimensional Models ◽  
Three Dimensional Models

Purpose The purpose of this study is structural stability evaluation of umbilical winch. In accordance with the recent trend for developing natural resources, high-technology equipment on exploration ships is becoming more technologically advanced. One such piece of high-technology equipment is the umbilical winch. In this study, the umbilical winch is divided into two parts (drum and winch), where each is respectively designed with three dimensional models using CATIA, and dynamic simulation and structural analysis are performed using ANSYS. Design/methodology/approach In this paper, the winch is divided into two parts for finite element analysis, the drum and whole winch model, and the parts are designed as three-dimensional models except for some small parts, such as bolt holes. Dynamic simulation and structural analysis are then performed using ANSYS. The analysis results ensure the reliability of the design methods and will be used in the domestic localization of remote operated vehicle (ROV) launch and recovery systems (LARS). Findings The strain is identified from the results, but it is very small. Some stress is concentrated at the lower corner of the drum, but the maximum stress value is lower than the allowable stress; therefore, the structure has no impact on the strain and stress. Thus, it is determined that the designed structure is safe. The results ensure the reliability of the design methods and will be used in the domestic localization of ROV LARS. Originality/value Previous studies focus on the static and mechanic problems of the winch by considering winch and drum breakage in the umbilical winch system. However, ships have a nonlinear motion characteristic with six degrees of freedom according to the constant influence of the external environment. In addition, from a design perspective, the dynamic characteristics (e.g. the ship’s motions) are more important than the static characteristics. Thus, the authors focus on winch stability securement with variable loads, such as ships moving, wave disturbance and other such important environment conditions.

Three-dimensional stochastic vortex flows

1989 ◽  
Vol 11 (4) ◽  
pp. 431-445 ◽  
Author(s):  
R. Esposito ◽  
M. Pulvirenti ◽  
H. Neunzert
Keyword(s):  
Three Dimensional ◽  
Vortex Flows

Three-Dimensional Vortex Flows of Two–Velocity Incompressible Media in the Case of Constant Volume Saturation

2015 ◽  
Vol 211 (6) ◽  
pp. 760-766
Author(s):  
N. M. Zhabborov ◽  
Kh. Kh. Imomnazarov ◽  
P. V. Korobov
Keyword(s):  
Three Dimensional ◽  
Constant Volume ◽  
Vortex Flows ◽  
Incompressible Media

Numerical investigations of vortex flows and vortex suppression schemes in a large pumping-station sump

2011 ◽  
Vol 225 (6) ◽  
pp. 1459-1480 ◽  
Author(s):  
X L Tang ◽  
F J Wang ◽  
Y J Li ◽  
G H Cong ◽  
X Y Shi ◽  
...  
Keyword(s):  
Free Surface ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Complex Nature ◽  
Stable Operation ◽  
Vortex Flows ◽  
Pumping Station ◽  
Pump Station ◽  
Pump Sump ◽  
Under Construction

This work uses a commercial computational fluid dynamics code to predict three-dimensional (3D) vortex flows in a large centrifugal-pump station under construction in China and proposes relevant vortex-eliminating schemes. Because of the complex nature of the vortex flows in sumps, different turbulence models, namely, standard k–ε, re-normalization group k–ε and realizable k–ε models, are first used to investigate their feasibility in predicting flows in a small physical model of an open pump sump, and various vortex streamlines and strength in the sump are predicted, analysed, and compared with the experimental data. The comparisons show that the realizable k–ε model predicts the position and strength of free-surface, sidewall-attached, and floor-attached vortices more accurately than the other two models. Then, the realizable k–ε model is used here to investigate 3D vortex flows in a large pumping-station sump. All the various vortices, such as free-surface, wall-attached vortices, are successfully predicted. Thus, based on the information of location, shape, size, and strength of the calculated vortices, three types of vortex-eliminating devices are proposed and their corresponding vortex suppression effects are analysed. These results will be used as reference for the safe and stable operation of the Hui–Nan–Zhuang pumping station in the future.

Instability of strongly nonlinear waves in vortex flows

1994 ◽  
Vol 269 ◽  
pp. 247-264 ◽  
Author(s):  
A. Kribus ◽  
S. Leibovich
Keyword(s):  
Linear Stability ◽  
Nonlinear Waves ◽  
Vortex Breakdown ◽  
Axisymmetric Flow ◽  
Three Dimensional ◽  
Vortex Flows ◽  
Weakly Nonlinear ◽  
Strongly Nonlinear ◽  
Perturbation Problem ◽  
Bending Modes

Weakly nonlinear descriptions of axisymmetric cnoidal and solitary waves in vortices recently have been shown to have strongly nonlinear counterparts. The linear stability of these strongly nonlinear waves to three-dimensional perturbations is studied, motivated by the problem of vortex breakdown in open flows. The basic axisymmetric flow varies both radially and axially, and the linear stability problem is therefore nonseparable. To regularize the generalization of a critical layer, viscosity is introduced in the perturbation problem. In the absence of the waves, the vortex flows are linearly stable. As the amplitude of a wave constituting the basic flow increases owing to variation in the level of swirl, stability is first lost to non-axisymmetric ‘bending’ modes. This instability occurs when the wave amplitude exceeds a critical value, provided that the Reynolds number is larger enough. The critical wave amplitudes for instability typically are large, but not large enough to create regions of closed streamlines. Examination of the most-amplified eigenvectors shows that the perturbations tend to be concentrated downstream of the maximum streamline displacement in the wave, in a position consistent with the observed three-dimensional perturbations in the interior of a bubble type of vortex breakdown.

Direct observation of spatial configuration and structural stability of locked Y-shaped DNA structure

RSC Advances ◽  
2016 ◽  
Vol 6 (105) ◽  
pp. 103270-103274 ◽  
Author(s):  
Tapas Paul ◽  
Padmaja P. Mishra
Keyword(s):  
Structural Properties ◽  
Structural Stability ◽  
Direct Observation ◽  
Single Molecule ◽  
Building Block ◽  
Spatial Configuration ◽  
Three Dimensional ◽  
Dna Structure ◽  
Bottom Up ◽  
Single Molecule Fret

A new building block unit (locked Y-DNA) and its structural properties for self-assembled, bottom-up, three-dimensional supramolecular nanoarchitectural probe ​have been introduced using single-molecule FRET imaging.

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