Numerical Investigation on the Influence of Gas Area Fraction on Developing Flow in a Pipe Containing Superhydrophobic Transverse Grooves

Abstract

This study presents a numerical investigation on the entrance length for developing flow in a pipe having alternating superhydrophobic grooves and ribs arranged transversely to the flow direction. Flows at low Reynolds number (i.e., = 1) over superhydrophobic transverse grooves of = 0.1 are considered. The influences of superhydrophobic surfaces on radial velocity profile development, centerline velocity distribution and hydrodynamic entrance length estimation are examined. Numerical results show that the hydrodynamic entrance length arising from flow over superhydrophobic transverse grooves are longer as compared to that of smooth wall. It is also found that the resulted entrance length is directly influence by the relative surface area occupied by grooves (i.e., gas area fraction). When the gas area fraction is larger, it would yield an increase in the hydrodynamic entrance length.