Flow-Induced Vibrations of Single and Tandem Square Columns

2015 ◽  
Author(s):  
Guan Meng Zhao ◽  
Narasimha Rao Pillalamarri ◽  
Ravi Chaithanya Mysa ◽  
Rajeev K. Jaiman
Keyword(s):  
Transverse Load ◽  
Circular Cylinders ◽  
Bluff Bodies ◽  
Arbitrary Lagrangian Eulerian ◽  
Response Dynamics ◽  
Tandem Arrangement ◽  
Fluid Forces ◽  
Flow Induced Vibrations ◽  
Load Component ◽  
Phase Angles

This work reports a set of numerical experiments to understand flow-induced vibrations of the square columns kept in a tandem arrangement. Results on the coupled force and response dynamics are presented for an isolated column and for a pair of square columns in the tandem configuration where downstream column is elastically mounted and free to oscillate in in-line and transverse directions. We assess the combined wake-induced and sharp-corner based galloping effects on the downstream column by comparing with the isolated square column counterpart. It is known that the circular cylinders undergo vortex-induced motion alone whereas motion of a square column is vortex-induced at low Re and galloping at high Re. The simulations are performed by means of a Petrov-Galerkin based finite-element solver using Arbitrary Lagrangian-Eulerian technique to account for the fluid mesh motion. The predicted results of the isolated column agree well with the available numerical results in the literature. The dimensions of the square columns and the domain are set in order to a have total blockage area of 5 %. The effects of reduced velocity on the fluid forces, wake contours, and the phase angles are analyzed. This work is also an attempt to enhance our understanding on the origin of wake-induced vibrations in a tandem arrangement of bluff bodies. In the case of tandem arrangement, upstream vortex shifts the stagnation point on the downstream column to the lower suction region. Thus a larger lift force is observed for the downstream column as compared to a vibrating isolated column. Phase difference between the transverse load and velocity of the downstream column determines the extent of upstream wake interaction with downstream column. When the column velocity is in-phase with the transverse pressure load component, interaction of wake vortex with the downstream column is minimum. For higher reduced velocities (Ur > 15), the wake downstream is very wide and irregular and the phase angle is consistently close to 180°.

scholarly journals Fluctuating Fluid Forces of Two Circular Cylinders in Tandem Arrangement at Close Spacing.

2002 ◽  
Vol 68 (669) ◽  
pp. 1400-1406 ◽  
Author(s):  
Masaru MORIYA ◽  
Mahbub ALAM ◽  
Kazunori TAKAI ◽  
Hiroshi SAKAMOTO
Keyword(s):  
Circular Cylinders ◽  
Tandem Arrangement ◽  
Fluid Forces ◽  
Close Spacing

scholarly journals Flow-Induced Vibrations of Single and Multiple Heated Circular Cylinders: A Review

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8496
Author(s):  
Ussama Ali ◽  
Md. Islam ◽  
Isam Janajreh ◽  
Yap Fatt ◽  
Md. Mahbub Alam
Keyword(s):  
Heat Transfer ◽  
Vortex Shedding ◽  
Heat Exchangers ◽  
Power Plants ◽  
Bluff Body ◽  
The Body ◽  
Circular Cylinders ◽  
Fluid Forces ◽  
Spacing Ratio ◽  
Flow Induced Vibrations

This study is an effort to encapsulate the fundamentals and major findings in the area of fluid-solid interaction, particularly the flow-induced vibrations (FIV). Periodic flow separation and vortex shedding stretching downstream induce dynamic fluid forces on the bluff body and results in oscillatory motion of the body. The motion is generally referred to as flow-induced vibrations. FIV is a dynamic phenomenon as the motion, or the vibration of the body is subjected to the continuously changing fluid forces. Sometimes FIV is modeled as forced vibrations to mimic the vibration response due to the fluid forces. FIV is a deep concern of engineers for the design of modern heat exchangers, particularly the shell-and-tube type, as it is the major cause for the tube failures. Effect of important parameters such as Reynolds number, spacing ratio, damping coefficient, mass ratio and reduced velocity on the vibration characteristics (such as Strouhal number, vortex shedding, vibration frequency and amplitude, etc.) is summarized. Flow over a bluff body with wakes developed has been studied widely in the past decades. Several review articles are available in the literature on the area of vortex shedding and FIV. None of them, however, discusses the cases of FIV with heat transfer. In particular systems, FIV is often coupled to heat transfer, e.g., in nuclear power plants, FIV causes wear and tear to heat exchangers, which can eventually lead to catastrophic failure. As the circular shape is the most common shape for tubes and pipes encountered in practice, this review will only focus on the FIV of circular cylinders. In this attempt, FIV of single and multiple cylinders in staggered arrangement, including tandem and side-by-side arrangement is summarized for heated and unheated cylinder(s) in the one- and two-degree of freedom. The review also synthesizes the effect of fouling on heat transfer and flow characteristics. Finally, research prospects for heated circular cylinders are also stated.

scholarly journals Visualization and Fluid Forces onthe Flow around a Pair of Circular Cylinders with Tandem Arrangement

2000 ◽  
Vol 2000 (0) ◽  
pp. 79
Author(s):  
Hiromichi OBARA ◽  
Yasuaki MATSUDAIRA ◽  
Makiko KOYAMA ◽  
Kentaro TANAKA
Keyword(s):  
Circular Cylinders ◽  
Tandem Arrangement ◽  
Fluid Forces

The Effect of Gap Flow on Vortex-Induced Vibration of Side-by-Side Cylinder Arrangement

2016 ◽  
Author(s):  
Bin Liu ◽  
Rajeev K. Jaiman
Keyword(s):  
Offshore Structures ◽  
Circular Cylinders ◽  
Bluff Bodies ◽  
Floating Platform ◽  
Additional Time ◽  
Vortex Induced Vibration ◽  
Stable Regime ◽  
Gap Flow ◽  
Flow Induced Vibrations ◽  
Lock In

A numerical investigation of vortex-induced vibration (VIV) of a pair of identical circular cylinders placed side by side in an uniform flow has been performed. One of the cylinder is elastically mounted and only vibrates in the transverse direction, while its counterpart remains stationary. When two cylinders are placed sufficiently close to each other, a flip-flopping phenomenon can be an additional time-dependent disturbance in the range of 0.2 ≲ g* ≲ 1.2. This phenomenon was well-reported by the experimental work of Bearman and Wadcock [1] in a side-by-side circular cylinder arrangement, in which the gap flow biased toward one of the cylinders and switched the sides intermittently. Albeit one of the two cylinders is free to vibrate, this flip-flopping during VIV dynamics can still be observed. In the side-by-side arrangement, the lock-in region shrinks due to the presence of its stationary counterpart and occurs prematurely compared to that of an isolated counterpart. Similar to the tandem cylinder arrangement, in the post lock-in region, the vibration amplitude is amplified compared to the isolated counterpart. For the vibrating cylinder in the side-by-side arrangement, the biased gap flow shows a quasi-stable flow regime within the lock-in region, instead of a bi-stable regime which is reported in the stationary side-by-side arrangement. When these factors take place simultaneously, the dynamics of freely vibrating cylinder becomes complex and such a side-by-side canonical arrangement is common in offshore engineering applications, for example a floating platform operating in the side of FPSO, arrays of riser and pipelines, ships travelling in rows within close proximity and many other side-by-side operations. The chaotic fluctuation and large vibration may occur when two bluff bodies are placed closely. It often causes inevitable damages and potential risks to the offshore structures and may leads to a collision or long-term fatigue failure associated with flow-induced vibrations.

scholarly journals Fluctuating Fluid Forces Acting on Two Circular Cylinders in a Tandem Arrangement at a Subcritical Reynolds Number

2001 ◽  
Vol 2001 (89) ◽  
pp. 697-724
Author(s):  
M. Moriya ◽  
Md. Mahbub Alam ◽  
K. Takai ◽  
H. Sakamoto ◽  
Masaru MATSUMOTO ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Circular Cylinders ◽  
Tandem Arrangement ◽  
Fluid Forces
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