Two-degree-of-freedom vortex-induced vibrations of a spring-mounted rigid cylinder with low mass ratio

2008 ◽  
Vol 24 (6) ◽  
pp. 907-919 ◽  
Author(s):  
A. Sanchis ◽  
G. Sælevik ◽  
J. Grue
Keyword(s):  
Degree Of Freedom ◽  
Mass Ratio ◽  
Rigid Cylinder ◽  
Vortex Induced Vibrations ◽  
Low Mass ◽  
Low Mass Ratio ◽  
Two Degree Of Freedom

VIV Control and Drag Reduction Using the Guided Porosity Concept

2008 ◽  
Author(s):  
Antonio C. Fernandes ◽  
Fabio M. Coelho ◽  
Ricardo Franciss ◽  
Severino F. S. Neto
Keyword(s):  
Drag Reduction ◽  
Potential Theory ◽  
Experimental Tests ◽  
Experimental Results ◽  
Mass Ratio ◽  
Vortex Induced Vibrations ◽  
Low Mass ◽  
Low Mass Ratio ◽  
Moving Parts

This paper aims to discuss the effectiveness of a new passive kind of VIV (Vortex Induced Vibrations) suppression. Moreover, the proposed solutions leads to a significant drag reduction when compared with conventional proposals (strakes for instance). The concept of guided porosity is applied in experimental tests conducted with low mass ratio cylindrical models. The works also shows that the job (VIV control and drag reduction) is achieved without moving parts, in contrast with segmented fairings. It also advances in terms of the omnidirectional solution. Initially, the concept is discussed in terms of the potential theory. Then experimental results are presented in terms of displacements and forces.

Numerical Simulation of the Multiple Branch Transverse Response of a Low Mass Ratio Elastically Supported Circular Cylinder

2006 ◽  
Author(s):  
Richard H. J. Willden
Keyword(s):  
Circular Cylinder ◽  
Maximum Amplitude ◽  
Mass Ratio ◽  
Large Eddy Simulation Model ◽  
Eddy Simulation ◽  
Vortex Induced Vibrations ◽  
Low Mass ◽  
Low Mass Ratio ◽  
Elastically Supported ◽  
High Degree

The paper presents the results of a numerical investigation of the transverse Vortex-Induced Vibrations of an undamped, low mass ratio elastically supported circular cylinder that was subjected to a uniform flow that resulted in a Reynolds number of 104. The numerical simulations were performed using a two-dimensional Large Eddy Simulation model. The computed cylinder response exhibits three branches; the initial, upper and lower branches. The computed initial and lower branches, which exhibit 2S and 2P modes of shedding respectively, show many similarities to those reported from experiments. However, the computed upper branch, on which a maximum amplitude of response of 0.83D was achieved, shows some dissimilarities to those reported from experiments. The failure to correctly simulate the upper branch response is thought to be due to the high degree of flow three-dimensionality that has been reported to exist on the upper branch.

Numerical Simulation of Two-Degree-of-Freedom Vortex-Induced Vibration of a Circular Cylinder Between Two Lateral Plane Walls in Steady Currents

2012 ◽  
Vol 134 (10) ◽  
Author(s):  
Ming Zhao ◽  
Feifei Tong ◽  
Liang Cheng
Keyword(s):  
Numerical Simulation ◽  
Circular Cylinder ◽  
Mass Ratio ◽  
Vortex Induced Vibration ◽  
Lateral Plane ◽  
Low Mass ◽  
Low Mass Ratio ◽  
Lock In ◽  
Two Degree Of Freedom ◽  
Lateral Walls

Vortex-induced vibration (VIV) of a circular cylinder at a low mass ratio of 1.5 between two lateral walls is investigated numerically. The focus of the study is to examine the effects of the two lateral walls on the VIV. Numerical simulations are carried out for w/D = 4, 6, 10, and 20 with D and w being the cylinder diameter and the distance between the two walls, respectively. It is found that the effects of the two walls on the VIV are obvious as w/D ≤ 6 and negligibly small as w/D = 10. The VIV amplitudes in both x- and y-directions increase with the increasing w/D in the lock-in regime.

scholarly journals Photometric Analysis of Wide and Narrow Hα Band Observations of R Canis Majoris

1992 ◽  
Vol 151 ◽  
pp. 303-306
Author(s):  
M. Taghi Edalati ◽  
Timothy Banks ◽  
Edwin Budding
Keyword(s):  
Hot Spot ◽  
Optimal Estimate ◽  
Mass Ratio ◽  
Transfer Effects ◽  
Photometric Analysis ◽  
Index Variation ◽  
Algol System ◽  
Low Mass ◽  
Low Mass Ratio ◽  
Optimisation Technique

Wide and narrow Hα lightcurves of R CMa were analysed using Wilson-Devinney (WD) and Information Limit Optimisation Technique (ILOT) approaches. A range of mass ratios, tested by both methods, led to an optimal estimate of around 0.45, at variance with the spectroscopic value. The distortion on the light curve affects the modelling, and so, in a second fitting, this was represented by a ‘hot spot’, associated with mass transfer effects. A semi-detached configuration was then derived. This is supported by the form of the Hα index variation, which has also been modelled. Although thus appearing as a ‘classical Algol’ system, R CMa retains its inherent peculiarity of low mass ratio with low period, which cannot be reconciled with conservative evolution scenarios.

scholarly journals Marginally low mass ratio close binary system V1191 Cyg

New Astronomy ◽  
2012 ◽  
Vol 17 (1) ◽  
pp. 46-49 ◽  
Author(s):  
B. Ulaş ◽  
B. Kalomeni ◽  
V. Keskin ◽  
O. Köse ◽  
K. Yakut
Keyword(s):  
Binary System ◽  
Close Binary System ◽  
Close Binary ◽  
Mass Ratio ◽  
Low Mass ◽  
Low Mass Ratio
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