Image automasking for dual-sided stereo PIV measurements of wind-driven waves

An automasking technique for multiphase interface identificantion is presented, along with sample application to Time Resolved PIV measurements of wind-driven wave flow. Measurements are performed on both sides of air-water interface in order to study the coupling between air and fluid motion. High resolution and dynamic range in space and time and accurate interface identification are required to resolve relevant flow scales along a complex and ever-changing interface. Approaches to obtain near-boundary measurement on both sides of interface are discussed, including optimal flow seeding procedures, illumination, data analysis, and interface tracking. Techniques are applied to the IIHR Boundary-Layer Wind-Wave Tunnel. The facility combines a 30m long recirculating water channel with an open-return boundary layer wind tunnel, allowing for the study of boundary layer turbulence interacting with a wind-driven wave field.