Laboratory Observations of Variable Size and Shape Particles: Artificial Sand and Oil Agglomerates

Following marine oil spills, weathered oil can mix with sediment in the surf zone and settle to the seafloor to form mats up to hundreds of meters long. Wave action fragments these mats into 1 to 10 cm diameter sand and oil agglomerates (SOAs). SOAs can persist for years, becoming buried in or exhumed from the seafloor and/or transported cross-shore and alongshore (Dalyander and others, 2015). These fragments are angular near the source mat and become increasingly rounded as they are transported. To quantify SOA motion, the U.S. Geological Survey (USGS) conducted experiments in November 2016 (field activity number 2016-364-DD) and June 2017 (field activity number 2017-329-FA) using various size, shape, and density artificial sand and oil agglomerates (aSOAs). Video and velocity data were collected under a range of hydrodynamic forcing in the Small-Oscillatory Flow Tunnel at the U.S. Naval Research Laboratory in Stennis, Mississippi. Between November 14-18, 2016, laboratory studies were conducted on spherical and patty shaped particles on a roughened flat bed. Two types of particles were used, one consisting of paraffin wax and sand, another was machine fabricated out of aluminum and coated in sand. Between June 5-8, 2017, laboratory studies were conducted on spherical, patty, ellipsoidal, and angular-ellipsoidal particles using paraffin wax and sand, aluminum, and 3-D printed plastic particles.