Accession Number : AD0622365

Title :   THE EFFECTS OF SURFACE CURVATURE AND PROPERTY VARIATION ON CELLULAR CONVECTION,

Corporate Author : RAND CORP SANTA MONICA CALIF

Personal Author(s) : Davis,Stephen H. ; Segel,Lee A.

Report Date : OCT 1965

Pagination or Media Count : 37

Abstract : Linear and nonlinear effects on convection of surface curvature and fluid property variations with temperature are considered in a fluid layer heated from below. It is found that the critical Rayleigh number R and corresponding critical wave number of linear theory can each either increase or decrease slightly from its constant property values, depending on the exact nature of the small property variations. If at least one property is considered as temperature dependent, stable hexagonal cells are predicted whether or not surface deflection is taken into account. If all fluid properties are considered constant, stable hexagonal cells are predicted for a layer bounded by a rigid plane below and a free surface above only if surface deflection is taken into account. Twodimensional 'rolls' are predicted as the stable convective mode in two cases: (i) when R exceeds its linear-theory critical value, if hexagons are unstable, and (ii) at a somewhat higher value of R, if hexagons are stable. (Author)

Descriptors :   (*CONVECTION, LAMINAR FLOW), (*LAMINAR FLOW, STABILITY), THERMAL EXPANSION, THERMAL DIFFUSION, VISCOSITY, PERTURBATION THEORY, SURFACE PROPERTIES, TEMPERATURE, NONLINEAR DIFFERENTIAL EQUATIONS

Distribution Statement : APPROVED FOR PUBLIC RELEASE