We present preliminary numerical simulations of tilted-disk accretion around a rotating black hole. Our goal is to explore whether hydrodynamic instabilities near the Bardeen-Petterson radius could be responsible for generating moderate-frequency quasi-periodic oscillations in X-ray binaries. We review the relevant general relativistic hydrodynamic equations, and discuss preliminary results on the structure and dynamics of a thin, Keplerian disk.

• GRANT J. MATHEWS(Center for Astrophysics, University of Notre Dame)
• P. CHRIS FRAGILE(Center for Astrophysics, University of Notre Dame)
• JANES R. WILSON(Lawrence Livermore National Laboratory)