On the Added Mass of a Sphere in a Circular Cylinder Considering Real Fluid Effects

Citation

Mellsen, Stanley Brun (1966) On the Added Mass of a Sphere in a Circular Cylinder Considering Real Fluid Effects. Engineer's thesis, California Institute of Technology. doi:10.7907/63N8-1N50. https://resolver.caltech.edu/CaltechTHESIS:10052015-161503645

Abstract

An experimental method combined with boundary layer theory is given for evaluating the added mass of a sphere moving along the axis of a circular cylinder filled with water or oil. The real fluid effects are separated from ideal fluid effects.

The experimental method consists essentially of a magnetic steel sphere propelled from rest by an electromagnetic coil in which the current is accurately controlled so that it only supplies force for a short time interval which is within the laminar flow regime of the fluid. The motion of the sphere as a function of time is recorded on single frame photographs using a short-arc multiple flash lamp with accurately controlled time intervals between flashes.

A concept of the effect of boundary layer displacement on the fluid flow around a sphere is introduced to evaluate the real fluid effects on the added mass. Surprisingly accurate agreement between experiment and theory is achieved.

Thesis Files