| Description |
Following oil spills such as the 2010 Deepwater Horizon blowout, residual oil can mix with sediment in the surf and swash zones and form a 70-80% sand mixture that sinks to the seafloor as sand and oil agglomerates (SOAs) ranging in size from centimeter-scale patties to meter-scale mats. Smaller SOAs (sub-meter scale) can be transported onshore and alongshore and may be either be angular (recently formed) or more rounded as a result of tumbling over the seafloor. Numerical studies have found that SOAs are likely to become buried and re-exhumed due to their large size relative to sand. These processes can result in concealment, exposure and potential transport of SOAs and reoiling of previously remediated beaches. Predicting SOA dynamics relies on accurate parameterization of incipient motion as well as formulations for their transport and seafloor interaction. Previous studies have found that shear-stress based formulations typically used for sand do not capture observed SOAs dynamics. In order to improve predictions of SOA mobility and transport, experiments utilizing artificial SOAs of various size, shape, and density are being conducted in an oscillatory flow tunnel. The data from these experiments will be used to increase the accuracy of formulations for SOA dynamics, thus improving numerical models that can be applied to assist oil spill remediation efforts. |
