Modeling Turbulent Jets Using Turbulence Models Developed for Hydrodynamic Instability-Induced Turbulent Mixing

The hydrodynamics in inertial confinement fusion (ICF) capsules imploded by laser energy is very complex, involving both weakly-nonlinear Rayleigh–Taylor (RT) and Richtmyer–Meshkov (RM) instability growth and potentially turbulent mixing. In addition to these instabilities, other flow features are present such as jets produced from fill tubes and other structural elements in the targets. Thus far, the emphasis of turbulence modeling in ICF capsules has been on hydrodynamic instability-induced mixing: the models have been optimized and calibrated to predict canonical RT and RM flows. This raises the question of whether such models can also reasonably predict turbulent jets interacting with mixing layers. Using numerical solutions to the self-similar incompressible turbulent jet equations with coefficients used in K–ε and K–L-based RT and RM models, it is shown that these models cannot adequately predict key properties of such jets. An explanation for this is provided and further discussed.