Accession Number:

AD0274927

Title:

THE ADDED MASS AND DAMPING OF TWO CYLINDERS OSCILLATING IN LIQUID HELIUM II

Descriptive Note:

Corporate Author:

ARMY RESEARCH OFFICE DURHAM N C

Personal Author(s):

Report Date:

1962-03-01

Pagination or Media Count:

1.0

Abstract:

The added mass and damping of two circular cylinders oscillating in liquid helium II were observed with a torsion pendulum and compared with a viscous fluid theory due to Stokes. The cylinders were Lucite rods .32 cm radius constrained to move with their axes parallel to and equidistant from the axis of rotation by means of Lucite end plates. The effect of a rigid cylindrical boundary on the added mass is given by a boundary factor F, the principal terms of which are 2 2 2 4 r 8r a b 1 1 F 1 - 2 4 4 2 2a b - a where r sub 1 radius of each cylinder, a distance of each cylinders axis from axis of rotation and b radius of boundary. In the experiment, ar sub 1 5 and 8.6 br sub 1 11. The range of the experiment is given by .03 penetration depthr sub 1 .6 and .02 amplituder sub 1 0.62. Both the logarithmic decrement and the added moment of inertia are independent of amplitude. The observed logarithmic decrement is in agreement with theory. End effects reduce the added moment of inertia as much as 2 below predicted values. Author

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Distribution Statement:

APPROVED FOR PUBLIC RELEASE