Moving Contact Lines: from Giant Slip on Textured Substrates to Water Striders

IAM Seminar
September 17, 2012 10:00 pm

Speaker:  Prof. James J. Feng, Department of ChBE, Department of Mathematics, UBC

URL for Speaker:

Location:  LSK 460

Intended Audience:  Public

A three-phase contact line forms when a gas-liquid interface intersects a solid substrate, and a moving contact line presents a well-known singularity that cannot be computed using the conventional Navier-Stokes formalism. I will discuss the use of a diffuse-interface model for computing moving contact lines. The Cahn-Hilliard diffusion is known to regularize the singularity and makes possible a continuum-level computation. But relating the results to physical reality is subtle. I will show numerical results that suggest a well-defined sharp-interface limit, with a finite contact line speed that can be related to measurements. Then I will discuss applications including enhanced slip on textured substrates and propulsion of water striders on the air-water interface.