Fluctuating boundary layers in combined convection flows along a vertical surface
Abstract
The effect of buoyancy force on laminar boundary layer in two dimensional flow and heat transfer along a semiinfinite vertical surface, when the velocity of the oncoming stream oscillates in magnitude about a steady mean, is analysed. Two separate solutions valid for low and high frequency ranges are developed. It is found that for low frequency oscillations the phase angles of oscillatory components of skin friction and the rate of heat transfer increase as the Grashof number increases. For very high frequencies, the velocity field is of shearwave type unaffected by the mean flow; the phase lead in the skin friction is, then, π/4 and the rate of heat transfer fluctuation indicates a phase lag of π/2 over that of the free stream oscillations.
 Publication:

Czechoslovak Journal of Physics
 Pub Date:
 July 1980
 DOI:
 10.1007/BF01599913
 Bibcode:
 1980CzJPh..30..790S
 Keywords:

 Convective Flow;
 Convective Heat Transfer;
 Laminar Boundary Layer;
 Skin Friction;
 Unsteady Flow;
 Flow Velocity;
 Forced Convection;
 Free Convection;
 Free Flow;
 Grashof Number;
 S Waves;
 Velocity Distribution;
 Fluid Mechanics and Heat Transfer