Accession Number : AD0717492

Title :   Drag of Free-Falling Spheres in Water for Reynolds Numbers Near Critical.

Descriptive Note : Master's thesis,

Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CALIF

Personal Author(s) : Nolan,George Fred

Report Date : SEP 1970

Pagination or Media Count : 90

Abstract : Drag coefficients of free-falling spheres in water were determined in a 12-ft diameter tank. Nine spheres with weights ranging from 361 grams to 4587 grams were released from rest and their speeds measured 19.5 feet below the release point using orthonormal cinematography. The region on both sides of the critical Reynolds number was covered with Reynolds numbers ranging from 100,000 to 700,000. Spheres with Reynolds numbers less than the critical values displayed little scatter in their terminal velocities. The same was true for the heaviest sphere. However, spheres with Reynolds number immediately above the critical value frequently deviated from the normal trajectory and their speeds showed scatter as great as 20%. A plot of drag coefficient versus Reynolds number shows that free-falling spheres essentially conform to the wind tunnel results; the critical Reynolds number is unchanged and the drag coefficients differ no more than 20%, always being higher for the free-fall case. (Author)

Descriptors :   (*DRAG, SPHERES), (*POLYMERS, LUBRICANTS), ADDITIVES, SKIN FRICTION, WATER, REYNOLDS NUMBER, FREE FALL MODELS, THESES

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE