S. Kyomen et al., COMBINED FREE AND FORCED-CONVECTION FOR LAMINAR STEADY FLOW IN HORIZONTAL TUBES, JSME international journal. Series B, fluids and thermal engineering, 39(1), 1996, pp. 44-50
It is well known that free convection is caused by the buoyancy forces
of a laminar steady flow in a heated pipe. However, this experimental
investigation shows that free convection occurs when the temperature
differences between air in a room and water in an unheated pipe are la
rge. Under such experimental conditions, the cross-sectional distribut
ions of axial velocities are obtained for water with ReRa (Re : Reynol
ds number, lia : Rayleigh number) as a parameter. Furthermore, a numer
ical analysis is also presented, and the calculated results are qualit
atively compared with the above experimental data of axial velocities
and those reported previously for air.