College of Science & Engineering
Twin Cities
These researchers are conducting computational research on atomizing fluids using a unique counterflow nozzle design. This design is known for achieving high mixing levels with minimal atomizing air. In addition to atomization, the group's research extends to examining shear layer instabilities in free shear layers subject to confinement, variable viscosity, and counterflow. Previous studies on Newtonian fluids have shown that counterflow can induce self-sustained oscillations and strong vortex formation, enhancing mixing rates. These oscillations are closely linked to absolutely unstable flow profiles. This study will apply linear stability theory to examine the atomization process and shear layer instabilities in non-Newtonian liquids when they interact with a counterflowing gas in a duct. The researchers focus on identifying the key wavelengths influenced by various factors: velocity profiles and counterflow rates, the fluid's power law exponent, Ohnesorge number, and the ratios of density, viscosity, and diameter. They plan to replicate conditions leading to absolute instability in laboratory experiments, observing global modes through self-sustained oscillations and uniform droplet sizes. The computations will employ Chebyshev spectral collocation methods within Scientific Python and leverage eigenvalue solvers from LAPACK.