  We present results of large eddy simulations of a cavitating nozzle flow and
injection into gas, investigating the interactions of cavitation in the nozzle,
primary jet breakup, mass-flow rates, and gas entrainment. During strong
cavitation, detached vapor structures can reach the nozzle outlet, leading to
partial entrainment of gas from the outflow region into the nozzle. The gas
entrainment can affect cavitation dynamics, mass-flow rates, and jet breakup.
Moreover, the implosion of detached vapor structures induces pressure peaks
that on the one hand amplify turbulent fluctuations and subsequently can
enhance jet breakup and on the other hand can damage walls in the proximity and
thus lead to cavitation erosion.
  Our numerical setup is based on a reference experiment, in which liquid water
is discharged into ambient air through a step nozzle. The cavitating liquid and
the non-condensable gas phase are modeled with a barotropic homogeneous mixture
model while for the numerical model a high-order implicit large eddy approach
is employed. Full compressibility of all components is taken into account,
enabling us to capture the effects of collapsing vapor structures. Two
operating points covering different cavitation regimes and jet characteristics
are investigated. Special emphasis is placed on studying the effects of
cavitation on the mass flow and the jet as well as the impact of partial gas
entrainment. Therefore, frequency analyses of the recorded time-resolved
signals are performed. Furthermore, the dynamics and intensities of imploding
vapor structures are assessed.
