TY - JOUR
TI - The characteristic length on natural convection from a horizontal heated plate facing downwards
AU - Kozanoglu Bulent
AU - Rubio Francisco
JN - Thermal Science
PY - 2014
VL - 18
IS - 2
SP - 555
EP - 561
PT - Article
AB - Natural convection from a downward facing horizontal heated plate was  analyzed. An expression for the thickness of the thermal boundary layer was  obtained in terms of Rayleigh number. Assuming this thickness as the  characteristic length of the problem, the data published by other authors  were modified and an equation for Nusselt number is presented. It was  observed that this equation correlates the data more precisely than the  commonly known equations in the literature that employ the ratio of the area  to the perimeter or the shorter side of the plate as the characteristic  length. It is concluded that taking the thermal boundary layer as the  characteristic length of phenomenon is a proper approach and correlates all  the data closely.