  We present a unified variational mechanics framework for cavitating turbulent
flows and structural motions via a stabilized finite element formulation. To
model the finite mass transfer rate in cavitation phenomena, we employ the
homogenous mixture-based approach via phenomenological scalar transport
differential equations. Stable linearizations of the finite mass transfer terms
for the mass continuity equation and the scalar transport equations are derived
for robust and accurate implementation. The linearized matrices for the
cavitation equation are imparted a positivity-preserving property to address
numerical oscillations arising from high-density gradients typical of two-phase
cavitating flows. The proposed formulation is strongly coupled in a partitioned
manner with an incompressible 3D Navier-Stokes finite element solver, and the
unsteady problem is advanced in time using a fully-implicit
generalized-$\alpha$ time integration scheme. We first verify the
implementation on the benchmark case of Rayleigh bubble collapse. We
demonstrate the accuracy and convergence of the cavitation solver by comparing
the numerical solutions with the analytical solutions of the Rayleigh-Plesset
equation for bubble dynamics. We find our solver to be robust for large time
steps and the absence of spurious oscillations in the pressure field. The
cavitating flow solver is coupled with a hybrid URANS-LES turbulence model with
a turbulence viscosity corrected for the presence of vapor. We validate the
coupled solver for a very high Reynolds number turbulent cavitating flow over a
NACA0012 hydrofoil section. Finally, the proposed method is solved in an
Arbitrary Lagrangian-Eulerian framework to study turbulent cavitating flow over
a pitching hydrofoil section and the coupled FSI results are explored for
characteristic features of cavitating flows such as re-entrant jet and periodic
cavity shedding.
