Abstract: For flowing of thin film containing insoluble surfactant over grooving substrate, lubrication theory is adopted for evolution equations of liquid film thickness and interfacial surfactant concentration. Film flowing characteristics and the effects of related parameters are numerically simulated. It shows that as thin film of insoluble surfactant flowing over grooving topography, gravity and Marangoni stress driven by surfactant promotes flow of liquid film. Gravity plays a leading role since influence of surfactant is limited by fl ows of surface liquid and adjacent bulk liquid. Viscous force associated with topography has an opposite effect. Film deformation is weak as improving Bond number or reducing capillary number. Increasing groove depth or decreasing groove steepness encourages film deformation as improving Marangoni stress.

Key words: surfactant, film, grooving topography, flow