Three-phase large eddy simulation of air–water–sand jets in crossflow

Subsea blowouts, a critical concern in offshore operations, typically entail a complex mixture of gas, liquid (oil/water), and sand, resulting in the formation of three-phase jets in crosscurrents. To understand the flow field and particle dynamics in air–water–sand three-phase jets in crossflow, a large eddy simulation was conducted using an Eulerian–Eulerian–Lagrangian three-phase model and cross-validated with the flume experimental results. The validated model confirmed that classical single-phase jet scaling laws remain applicable to three-phase jets in crossflow, while revealing a new power-law scaling rule for the radii of the multiphase buoyant jets with different velocity ratios. Additionally, the transition of sand concentration profiles from weak to strong deflection was found to occur when the height above the nozzle reaches the jet-to-crossflow length scale. In the bubbly jet, bubbles enhanced the liquid-phase peak vertical velocity by up to 12.9% compared with the pure water jet, whereas sand particles reduced the peak vertical velocities of the liquid and gas phases in the three-phase jet by up to 33.8% and 16.8%, respectively, at the heights considered in the study. Sand spreading in the spanwise direction is governed primarily by the counter-rotating vortex pair (CVP). As the CVP dissipated downstream, the sand particles behaved like free-falling objects, exhibiting minimal variation in spanwise velocity, while the cross-sectional sand concentration distribution shifted from the initial upward-expanding pattern to the later downward-expanding pattern.