Figure 12.

Evolution of the axial velocity in the equatorial plane for a relativistic r-mode in a rapidly rotating N=1.0 polytrope (in the Cowling approximation). Since the initial data used to excite the mode are not exact, the evolution is a superposition of (mainly) the l=m=2 r-mode and several inertial modes. The amplitude of the oscillation decreases due to numerical (finite-differencing) viscosity of the code. A beating between the l=m=2 r-mode and another inertial mode can also be seen. (Figure 2 of Stergioulas and Font [294].)