Numerical Study on Vortex Induced Vibrations of Four Cylinders in an In-Line Square Configuration

2009 ◽  
pp. 553-567 ◽  
Author(s):  
Feng Xu ◽  
Jinping Ou ◽  
Yiqing Xiao
Keyword(s):  
Numerical Study ◽  
Vortex Induced Vibrations ◽  
Square Configuration ◽  
Four Cylinders

Vortex-Induced Vibrations of a Cylinder at Subcritical Reynolds Number

2011 ◽  
Author(s):  
Yoann Jus ◽  
Elisabeth Longatte ◽  
Jean-Camille Chassaing ◽  
Pierre Sagaut
Keyword(s):  
Reynolds Number ◽  
Numerical Simulations ◽  
Numerical Study ◽  
Damping Ratio ◽  
Experimental Studies ◽  
Cross Flow ◽  
Physical Analysis ◽  
Arbitrary Lagrangian Eulerian ◽  
Vortex Induced Vibrations ◽  
Low Mass

The present work focusses on the numerical study of Vortex-Induced Vibrations (VIV) of an elastically mounted cylinder in a cross flow at moderate Reynolds numbers. Low mass-damping experimental studies show that the dynamic behavior of the cylinder exhibits a three-branch response model, depending on the range of the reduced velocity. However, few numerical simulations deal with accurate computations of the VIV amplitudes at the lock-in upper branch of the bifurcation diagram. In this work, the dynamic response of the cylinder is investigated by means of three-dimensional Large Eddy Simulation (LES). An Arbitrary Lagrangian Eulerian framework is employed to account for fluid solid interface boundary motion and grid deformation. Numerous numerical simulations are performed at a Reynolds number of 3900 for both no damping and low-mass damping ratio and various reduced velocities. A detailed physical analysis is conducted to show how the present methodology is able to capture the different VIV responses.

Experimental and Numerical Study of Vortex Induced Vibrations on a Spool Model

2018 ◽  
Author(s):  
David Gross ◽  
Yann Roux ◽  
Benjamin Rousse ◽  
François Pétrié ◽  
Ludovic Assier ◽  
...  
Keyword(s):  
Stokes Equations ◽  
Numerical Study ◽  
Fluid Dynamic ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Flow Perturbation ◽  
Industry Standards ◽  
Vortex Induced Vibrations ◽  
Recommended Practices ◽  
Decay Tests

The problem of Vortex-Induced Vibrations (VIV) on spool and jumper geometries is known to present several drawbacks when approached with conventional engineering tools used in the study of VIV on risers. Current recommended practices can lead to over-conservatism that the industry needs to quantify and minimize within notably cost reduction objectives. Within this purpose, the paper will present a brief critical review of the Industry standards and more particularly focus on both experimental and Computational Fluid Dynamic (CFD) approaches. Both qualitative and quantitative comparisons between basin tests and CFD results for a 2D ‘M-shape’ spool model will be detailed. The results presented here are part of a larger experimental and numerical campaign which considered a number of current velocities, heading and geometry configurations. The vibratory response of the model will be investigated for one of the current velocities and compared with the results obtained through recommended practices (e.g. Shear7 and DNV guidelines). The strategy used by the software K-FSI to solve the fluid-structure interaction (FSI) problem is a partitioned coupling solver between fluid solver (FINE™/Marine) and structural solvers (ARA). FINE™/Marine solves the Reynolds-Averaged Navier-Stokes Equations in a conservative way via the finite volume method and can work on structured or unstructured meshes with arbitrary polyhedrons, while ARA is a nonlinear finite element solver with a large displacement formulation. The experiments were conducted in the BGO FIRST facility located in La Seyne sur Mer, France. Particular attention was paid towards the model design, fabrication, instrumentation and characterization, to ensure an excellent agreement between the structural numerical model and the actual physical model. This included the use of a material with low structural damping, the performance of stiffness and decay tests in air and in still water, plus the rationalization of the instrumentation to be able to capture the response with the minimum flow perturbation or interaction due to instrumentation.

Interaction of Asymmetric Films Around Boiling Cylinder Array: Homogeneous Interface to Chaotic Phenomenon

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Akash Deep ◽  
Chandan Swaroop Meena ◽  
Arup Kumar Das
Keyword(s):  
Source Term ◽  
Film Growth ◽  
Numerical Study ◽  
Film Boiling ◽  
Water Pool ◽  
Time Interaction ◽  
Saturated Water ◽  
Finite Volume Discretization ◽  
Horizontal Cylinders ◽  
Four Cylinders

We report numerical study of film boiling around hot and horizontal cylinders in a saturated water pool to establish interfacial interactions leading toward dryout. Volume of fluid-based finite-volume discretization is performed in the domain for incorporation of source term in mass momentum and energy conservation equations due to phase change. At first, film boiling around single cylinder is simulated at different surface temperatures to understand unconstrained film growth and subsequent film bubble release due to buoyancy. Using velocity vectors and temperature contours, effect of film flow dynamics on bubble departure is depicted. This study has been extended further with multiple cylinders in three different stacking arrangements in order to understand the interaction of films in vicinity. Vertical interaction between cylinders leads to suppression of bubble release at the lower cylinder in comparison to the upper one. In the case of horizontal interactions, bubbles attract each other and merge, provided favorable pitch between cylinders and temperatures of the surfaces is maintained. Offset four cylinders stack maintaining vertical and horizontal pitch allows both lateral vapor affinity and bubble suppression in the lower most cylinder simultaneously. With time interaction of accumulated vapor films around cylinders hinders replenishment of fresh liquid to the hot surfaces leading toward chaotic phenomena or dryout in boiling heat transfer.

scholarly journals Numerical study on Modal Analysis of a typical bridge section with the influence of Aeroelastic effect

2019 ◽  
Vol 11 (4) ◽  
pp. 133-138 ◽  
Author(s):  
G. PRASAD
Keyword(s):  
Numerical Simulation ◽  
Modal Analysis ◽  
Mode Shape ◽  
Structural Design ◽  
Numerical Study ◽  
Analysis Software ◽  
Transportation Management ◽  
Structure Interaction ◽  
Vortex Induced Vibrations ◽  
Design Software

Due to the increase in the number of vehicles, transportation management is achieved through the construction of bridges. This article discusses the vibrational effect in the design of bridges. In the structural design of the bridges proper planning is necessary, as gusts may occur, leading to aeroelastic instabilities. In this article a typical bridge is designed using the design software CATIA and a numerical simulation using analysis software ANSYS. Further, the aeroelastic phenomenon involved in coupling of Fluid Structure Interaction is discussed. The results of Mode shape show vortex-induced vibrations which can lead to Flutter.

Numerical Analysis of Combined VIV and Slug Flow in Time Domain

2016 ◽  
Author(s):  
Tor Huse Knudsen ◽  
Svein Sævik ◽  
Mats Jørgen Thorsen
Keyword(s):  
Multiphase Flow ◽  
Time Domain ◽  
Slug Flow ◽  
Structural Model ◽  
Numerical Study ◽  
Two Phase ◽  
Marine Risers ◽  
Numerical Studies ◽  
Vortex Induced Vibrations ◽  
Internal Velocity

Vortex induced vibrations (VIV) and slug flow are two important aspects for marine risers conveying a multiphase flow, and should be carefully examined due to the influence on the fatigue life of the structure. This article examines a truncated riser exposed to VIV with an internal two-phase slug flow. The main focus of the article was to examine the effect of internal slug flow on the VIV of a riser. The VIV were simulated in time domain with a linear structural model with constant pretension. Approximately 150 vortex shedding periods were simulated after the response reached steady state. An internal two-fluid flow was introduced, with constant internal velocity, pressure and uniform slug lengths. From the numerical study it was apparent that the slug velocity and slug length had an influence on the response pattern, amplitude and frequency. An analytical model that predicts additional response frequencies due to slug flow was also compared to the numerical studies. The analytical study produced similar additional response frequencies as the numerical study. The slug length and internal velocity can influence the response of the riser, and should be considered for marine risers conveying multiphase flow.

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