RAPID: Collaborative Research: Multiscale plume modeling of the Deepwater Horizon oil-well blowout for environmental impact assessment and mitigation

深水地平线（DH）意外油井井喷产生的地下羽流是一个复杂的分层侵入系统，其中含有石油、溶解的碳氢化合物和注入的分散剂，将对环境产生深远的影响；然而，目前还没有建模工具能够对羽流的结构和演化进行高分辨率的预测。本快速响应研究计划（Rapid）的目标是结合Reynolds平均Navier Stokes （RANS）建模方法和大涡模拟（LES）方法，为DH井喷羽流开发一个三维，多尺度流体动力学模型。最终的模型平台将根据现场和实验室数据进行验证，将尊重释放的石油和天然气的相关化学和热力学，并将受泄漏周围测量的环境条件的影响。我们迫切需要这样的模拟工具来指导现场观测，预测溢油的陆上迁移和环流捕获，评估在源头注入分散剂的有效性和潜在环境影响，并了解浮游生物和鱼类对这一事件的响应，这些响应已经在垂直迁移中得到了测量。经过验证的建模平台将通过补充实验室实验、数值模拟和现场数据分析来开发。实验室的实验将评估气流的影响，当气流穿过羽流并将石油和溶解成分拉入羽流的尾迹中时。数值方法将利用甚大涡模拟（VLES）来解析喷流近场的优势羽流结构，并将该模型嵌套到基于非定常RANS方法的远场模型中。来自声学多普勒电流剖面仪的现场数据将提供模型强迫和验证数据，还将分析地下羽流动力学对浮游生物和鱼类垂直迁移的作用，这些数据也记录在ADCP数据中。对这些数据的早期分析显示，在泄漏开始后不久，附近站点的日垂直迁移模式迅速关闭。这是对井喷的第一次有记录的环境反应，目前尚不清楚这是由于死亡、躲避、光线穿透变化还是其他过程。这里开发的地下羽流模型将提供分析这种环境响应所必需的地下羽流结构的详细预测。知识价值：该项目的主要知识价值将是对意外油井井喷中导致石油和溶解碳氢化合物在水柱中形成地下分层结构的关键物理和化学过程的理解。对于经典RANS模型用于预测油气侵入动态的适用性，也将获得重要的见解。更广泛的影响：该模型的预测将有助于指导现场观测数据的收集，并将应用于理解为什么井喷后不久，井喷附近的浮游生物和鱼类停止了它们的垂直迁移模式。该模型还需要用于预测石油和注入分散剂在整个海湾生态系统中的运输，包括陆上和进入环流，甚至可能进入大西洋。在项目后期进行的多相羽流湍流的详细研究将最终产生一个可靠的模型框架，该模型框架具有区域性ranss - vles模拟工具，适用于多相羽流的广泛环境应用，包括CO2固存，湖泊通气和沉积物羽流等。

The subsurface plume from the Deepwater Horizon (DH) accidental oil-well blowout is a complex, layered system of intrusions containing oil, dissolved hydrocarbons, and injected dispersants that will have far-reaching environmental consequences; however, no modeling tools are currently producing highly-resolved predictions of the plume structure and evolution. The goal of this Rapid Response Research Proposal (RAPID) is to develop a three-dimensional, multiscale hydrodynamic model for the DH blowout plume that combines the Reynolds averaged Navier Stokes (RANS) modeling approach with the method of large-eddy simulation (LES). The resulting model platform will be validated to field and laboratory data, will respect the relevant chemistry and thermodynamics of the released oil and natural gas, and will be forced by the measured ambient conditions surrounding the spill. Such a simulation tool is urgently needed to guide field observations, predict the onshore migration and loop-current capture of the spilled oil, assess the effectiveness and potential environment impact of dispersants injected at the source, and to understand the response to this event already measured in the vertical migration of plankton and fish. The validated modeling platform will be developed through complementary laboratory experiments, numerical modeling, and analysis of field data. The laboratory experiments will evaluate the effects of currents as the flow through the plume and pull oil and dissolved constituents into the wake of the plume. The numerical methods will utilize a very large eddy simulation (VLES) to resolve the dominant plume structures in the near field of the blowout plume and will nest this model in a far-field model based on the unsteady RANS approach. Field data from acoustic Doppler current profilers will provide model forcing and validation data and will also be analyzed to understand the role of subsurface plume dynamics on the vertical migration of plankton and fish as also recorded in the ADCP data. Early analysis of this data shows a very rapid shut-down of the diurnal vertical migration pattern at nearby stations shortly after the start of the spill. This is the first documented environmental response to the blowout, and it remains unknown whether this is due to mortality, avoidance, light penetration changes or other processes. The sub-surface plume model developed here will provide detailed predictions of the subsurface plume structure necessary to analyze this environmental response. Intellectual Merit: The primary intellectual merit of the project will be an understanding of the critical physical and chemical processes in an accidental oil-well blowout that lead to the subsurface layered structure of oil and dissolved hydrocarbons in the water column. Important insight will also be gained on the appropriateness of a classical RANS model for predicting the dynamics of the oil and gas intrusions. Broader Impact: Predictions from the model will help guide the collection of observation data in the field and will be applied to understand why plankton and fish in the vicinity of the blowout shut down their vertical migration pattern shortly after the blowout. The model is also needed to predict the transport of oil and injected dispersants throughout the Gulf ecosystem, including onshore and into the loop current and potentially into the Atlantic ocean. Detailed studies of turbulence in multiphase plumes conducted in the later stages of the project will ultimately result in a reliable model framework featuring a zonal RANS-VLES simulation tool applicable to a wide range of environmental applications of multiphase plumes, including CO2 sequestration, lake aeration, and sediment plumes, among others.