Influence of incompressible surfactant on drag in flow along an array of gas-filled grooves

Surfactants can have a detrimental effect on the drag reduction in shear flow over superhydrophobic surfaces Cassie state. Assuming an incompressible, inviscid surfactant phase at gas-liquid interfaces, we study liquid array of narrow gas-filled grooves embedded otherwise planar surface, with interface protruding above or below plane. A recirculating develops such that slip length for is much smaller than corresponding surfactant-free interfaces.