The Developing Plane Channel Flow over Water-Repellent Surface Containing Transverse Grooves and Ribs

Kok Hwa Yu; Yan Xu Tan; Mohd Sharizal Abdul Aziz; Yew Heng Teoh; Mohd Zulkifly Abdullah

Authors

Kok Hwa Yu School of Mechanical Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Penang, Malaysia
Yan Xu Tan School of Mechanical Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Penang, Malaysia
Mohd Sharizal Abdul Aziz School of Mechanical Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Penang, Malaysia
Yew Heng Teoh School of Mechanical Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Penang, Malaysia
Mohd Zulkifly Abdullah School of Mechanical Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Penang, Malaysia

Keywords:

Entrance length, superhydrophobic, surface roughness , laminar flow , wall slip

Abstract

This study presents a numerical investigation on developing flow in a plane channel having alternating superhydrophobic transverse grooves and ribs patterned on both upper and lower walls. Pressure-driven flow at low Reynolds number (i.e., = 1) is considered. The numerical results show that the presence of superhydrophobic surfaces has a visible influence on the velocity profile, centerline velocity and the hydrodynamic entrance length. It is worth highlighting that the hydrodynamic entrance length arising from flow over superhydrophobic transverse grooves are longer than that of smooth surface. This lead to suggestion that, by having transversely aligned groove mounted surface with hydrophobic coating, the fully developed flow region can be delayed. It is also found that, despite having the same gas area fraction, the scale of the microstructure features could directly influence the hydrodynamic entrance length, as well as the velocity profile and the centerline velocity distribution.