Motion of a circular cylinder in a viscous liquid between parallel plates

Experiments have been carried out on two-dimensional devices fitted to a rigid length of circular cylinder to investigate the efficiency of pivoting parallel plates as wake-induced vibration suppressors. Measurements are presented for a circular cylinder with low mass and damping which is free to respond in the cross-flow direction. It is shown how VIV and WIV can be practically eliminated by using free to rotate parallel plates on a pair of tandem cylinders. Unlike helical strakes, the device achieves VIV suppression with 33% drag reduction when compare to a pair of fixed tandem cylinders at the same Reynolds number. These results prove that suppressors based on parallel plates have great potential to suppress VIV and WIV of offshore structures with considerable drag reduction.

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Discussion: “Flow Past a Right Circular Cylinder in a Rotating Frame” (Boyer, D. L., 1970, ASME J. Basic Eng., 92, pp. 430–435)

Journal of Basic Engineering ◽

10.1115/1.3425023 ◽

1970 ◽

Vol 92 (3) ◽

pp. 435-436

Author(s):

S. J. Jacobs

Keyword(s):

Circular Cylinder ◽

Rossby Number ◽

Rotating Frame ◽

Two Dimensional ◽

Parallel Plates ◽

Extra Condition ◽

Ekman Number ◽

Flow Past ◽

Number Flow ◽

Interior Flow

An analysis of low Rossby number and low Ekman number flow between parallel plates shows that the interior flow is irrotational and two-dimensional for all Rossby numbers and Ekman numbers in the range R0≪1, E≪1. The extra condition R0≪E1/2 is not needed for this proof.

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The flow of viscous liquid past spinning bodies

Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character ◽

10.1098/rspa.1933.0183 ◽

1933 ◽

Vol 142 (847) ◽

pp. 491-508 ◽

Cited By ~ 5

Keyword(s):

Circular Cylinder ◽

Viscous Liquid ◽

Stokes Equations ◽

Slow Motion ◽

Two Dimensions ◽

The Body ◽

Three Dimensions ◽

Stream Velocity ◽

Flow Past ◽

Spinning Bodies

The motion produced in a viscous liquid by a spinning sphere has been investigated for small values of the Reynolds’ number, using Stokes’ equations for slow motion, in which the inertia terms are neglected.* By combining the solution for this problem with that given by Stokes for the flow of a stream of viscous liquid past a fixed sphere, we obtain the solution for a stream flowing past a spinning sphere. Oseen introduced a modified system of equations, in which the inertia terms are partly taken into account, and obtained the solution for flow past a fixed sphere using these equations. The problem of the flow of viscous liquid past a fixed circular cylinder has been investigated by Lamb,§ using Oseen’s equations, and the additional solution required if the cylinder is rotating has been given by Oseen.║In the present paper the solution for flow past a spinning sphere is discussed, using Oseen’s equations. The flow of viscous liquid past a spinning body is physically equivalent to motion of the body through the liquid with combined translation and rotation. Now it is well known that in practice when a body moves through a liquid in such a manner, if there is rotation about an axis y perpendicular to the direction of motion x , then ther is a lift on the body in a direction perpendicular to both x and y ¶. In theoretical investigation , if we suppose that the motion is steady, we are restricted in three dimensions to a body rotating about an axis of symmetry, and in two dimensions to the circular cylinder. In these cases it is impossible to obtain a lift if we use Stokes' equations for slow motion. For since that equations are linear, the lift is the sum of the lifts due to the solution for flow past a fixed body and the solution for spin without flow, and these are both zero by symmetry. This argument does not apply to Oseen's equations, since we cannot have a solution for spin alone with no flow, the stream velocity being implied in the equations themselves. In the absence of a method for solving the complete hydrodynamcial equations, it is therefore of interest to investigate the flow of viscous liquid past spinning bodies, using Oseen's equations, and particularly to find whether a lift is obtained.

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