Analyzing free-surface deformations for flow over submerged bedforms

Submerged features in a turbulent free-surface flow may leave an imprint on the water surface, but these surface expressions are difficult to distinguish from typical turbulent fluctuations. To characterize them, we implemented Polarimetric Slope Sensing (PSS), which allows us to measure spatiotemporal reconstructions of the free-surface deformations. We will present the results of laboratory experiments conducted in a 6m circulating water flume and analyzed using PSS for flow over a variety of canonical bedforms modeled after common submerged features in littoral and fluvial settings.