Computational Modeling of Hypersonic Droplet Aerobreakup

Adverse weather encounters impose a significant threat to hypersonic vehicles. Liquid droplet impacts during flight can negatively affect vehicle performance to varying degrees, ranging from reduced flight control and degraded sensor performance to catastrophic failure. During supersonic and hypersonic flight, droplets are processed by a shock and start to deform and break up before impacting the vehicle. As the droplet shape, speed, and mass at impact drive impact damage, a fundamental understanding of high-speed droplet breakup (aerobreakup) is essential for future high-speed vehicle designs.

The spatially conservative, compressible, multiphase solver in the open-source NGA2 computational suite (https://github.com/desjardi/NGA2) is used in this work to investigate high-speed shock-induced aerobreakup. NGA2 is characterized by its utilization of a Sharp Interface Method (SIM) for modeling liquid/gas interfaces.

Results from 2D and 3D shock/droplet simulations will be presented for flight-relevant conditions (shock Mach numbers from ~3-5). Quantities of interest (QOIs) include primary droplet mass, shape, and location as a function of time. Of particular interest is also investigating the growth of surface instabilities that drive droplet aerobreakup under high Mach # and high Weber # flow conditions. Results from this study will be compared to recent experiments and computations for the same flow conditions.