Development of Oil Spill Response Decision Support Tool for Aerial Spraying of Dispersants

Abstract

2017-280 Abstract This paper describes the development of a Decision Support Tool (DST) for response planning associated with aerial operations for offshore oil spills. The research program was formulated to include characterization of dispersant spray drift through numerical modeling to generate a database of drift response for a range of airframes and environmental conditions. The drift of aerial dispersants is dependent on a number of different influences including airframe shape and aerodynamics, environmental effects, flight conditions and aerial dispersant make up. As with agricultural spraying, oil spill response spraying has the potential of spray drift to impact upon ecologically sensitive regions and/or areas occupied by people or marine mammals surfacing in the spill area. The development of the DST included an evaluation of existing regulatory models, investigating their application to the offshore environment. It was found that, due to inherent limitations and simplifications, particularly for the larger airframes considered, the existing models were under conservative in comparison with Computational Fluid Dynamics (CFD) models in the near field wake regions for offshore spraying purposes. To address these issues, a combination of scaling factors and the use of inviscid vortex transport and particle dispersion models were adopted for inclusion in the DST. It is envisaged that, once validated further, the DST will become an invaluable tool for Oil Spill Response Operators (OSROs) and decision planners in both the operational mode of providing information to aid in establishing setback distances and in the planning mode to assist with the identification of windows of opportunity conducive to spraying operations.

Predicting the Aerial Application of Dispersant Onto an Oil Spill

“…For fixed-wing applications, the aircraft wake is represented by wingtip, flap, fuselage, and tail vortices, which play an important role in droplet breakup and the deposition pattern of the released dispersant on the water surface. Later publications suggest an evolving understanding of the role played by these vortices [3,[11][12][13][14][15]. The initial development of the airborne dispersant delivery system (ADDS) and the later development of the modular aerial spray system (MASS) for the Lockheed C-130 provided two deposition datasets [3,14] spraying Corexit 9527 dispersant (Corexit Environmental Solutions LLC, Sugar Land, TX) to field study sites.…”