Accession Number : AD0679020

Title :   A DIRECT-SHADOW METHOD FOR INVESTIGATING NATURAL CONVECTION IN WATER,

Corporate Author : HARRY DIAMOND LABS WASHINGTON D C

Personal Author(s) : Ulrich,Reinhard R.

Report Date : AUG 1968

Pagination or Media Count : 68

Abstract : A direct-shadow method was used to investigate circulations caused by natural convection in distilled water layers heated uniformly from below with depths ranging from 5 mm to 2.54 cm. The top- and side-view shadow patterns indicated changes in structure which corresponded to transitions in the heat transport rate through the fluid layer. A ray-tracing technique is described in which the relative spatial intensity distribution for light that passes through a fluid layer with a known temperature field can be constructed for any path length beyond the fluid layer. This method was used to determine the ray-distribution at various screen distances for parallel light indicent on a fluid band cell having a temperature field derived by Rayleigh. The relationship between the fluid temperature variations and the shadow-pattern light-intensity variations was established by experiments with a uniformly drifting fluid layer of 5-mm depth. These experiments showed that the relative temporal temperature variations at a point in the fluid were closely correlated with the second integral of the relative temporal light-intensity variations at a corresponding point in the shadow patterns. (Author)

Descriptors :   (*CONVECTION(HEAT TRANSFER), *PHOTOGRAPHY), (*FLUID FLOW, CONVECTION(HEAT TRANSFER)), FLOW VISUALIZATION, WATER, HEATING, TEMPERATURE, INTENSITY, OPTICAL SCANNING, THESES

Subject Categories : Photography
      Fluid Mechanics
      Thermodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE