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

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

Effect of a Vibrating Upstream Cylinder on a Stationary Downstream Cylinder

1986 ◽  
Vol 108 (2) ◽  
pp. 180-184 ◽  
Author(s):  
M. Moriya ◽  
H. Sakamoto
Keyword(s):  
Reynolds Number ◽  
Transverse Vibration ◽  
Flow Patterns ◽  
Uniform Flow ◽  
Circular Cylinders ◽  
Tandem Arrangement ◽  
Cylinder Diameter ◽  
Spacing Ratio ◽  
Lock In

The flow around two circular cylinders in tandem arrangement in uniform flow where the upstream cylinder is forcibly vibrated in direction normal to the approach flow was experimentally studied at Reynolds number of 6.54 × 104. The spacing ratio 1/d (1: distance between centers of cylinders, d: diameter of circular cylinders) and the ratio of amplitude to cylinder diameter a/d (a: amplitude of transverse vibration of cylinder) were varied from 2 to 6 and 0 to 0.029 respectively. The effects of the vibration of the upstream cylinder on the downstream cylinder were discussed. In particular, two distinct “lock-in” regions were observed when the upstream cylinder was vibrated with a spacing ratio of 1/d = 3.0. The cylinder vibration was so effective even for a/d as small as 0.017 to cause two different flow patterns.

Effect of Free-Stream Turbulence on Characteristics of Fluctuating Forces Acting on Two Square Prisms in Tandem Arrangement

1988 ◽  
Vol 110 (2) ◽  
pp. 140-146 ◽  
Author(s):  
H. Sakamoto ◽  
H. Haniu
Keyword(s):  
Reynolds Number ◽  
Strouhal Number ◽  
Turbulence Intensity ◽  
Vortex Shedding ◽  
Free Stream ◽  
Switching Frequency ◽  
Tandem Arrangement ◽  
Free Stream Turbulence ◽  
Fluid Forces ◽  
Bistable Flow

The effect of the addition of the turbulence intensity to the free stream on the characteristics of the bistable flow which takes place around two square prisms in tandem arrangement was studied experimentally at a Reynolds number of 3.32 × 104. A method of obtaining the fluid forces acting on two prisms in the bistable flow regimes where two flow patterns appear intermittently was introduced, and then the characteristics of the fluid forces, the Strouhal number, and the switching frequency of the switch phenomenon with the variation of the freestream turbulence intensity were investigated. Furthermore, the behavior of the fluid forces and the vortex shedding for other spacings between the two prisms were presented for the variation of the turbulence intensity.

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°.

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