  We have carried out 3-D numerical simulations of the dynamical bar
instability in a rotating star and the resulting gravitational radiation using
both an Eulerian code written in cylindrical coordinates and a smooth particle
hydrodynamics (SPH) code. The star is modeled initially as a polytrope with
index $n = 3/2$ and $T_{\rm rot}/|W| \approx 0.30$, where $T_{\rm rot}$ is the
rotational kinetic energy and $|W|$ is the gravitational potential energy. In
both codes the gravitational field is purely Newtonian, and the gravitational
radiation is calculated in the quadrupole approximation.
  We have run 3 simulations with the Eulerian code, varying the number of
angular zones and the treatment of the boundary between the star and the
vacuum. Using the SPH code we did 7 runs, varying the number of particles, the
artificial viscosity, and the type of initial model. We compare the growth rate
and rotation speed of the bar, the mass and angular momentum distributions, and
the gravitational radiation quantities. We highlight the successes and
difficulties of both methods, and make suggestions for future improvements.

General Relativity and Quantum Cosmology;Astrophysics