  We study the nonlinear dynamics of a warped or twisted accretion disc, in
which the viscosity coefficients are assumed to be locally proportional to the
rotational velocity (beta- prescription). Using asymptotic methods for thin
discs, dynamical equations of the disc are obtained in a warped spherical polar
coordinates. These equations are solved by the method of the separation of the
variables. This analysis constitutes an analogous study of the nonlinear theory
of an alpha model warped disc which has been studied by Ogilvie (1999). We have
compared our results with Ogilvie's analysis. The dynamical behaviors of these
models have also been discussed. Our results show that different viscosity
prescriptions and magnitudes (alpha and beta prescriptions) affect dynamics of
a warped accretion disc. Therefore it can be important in determining the
viscosity law even for a warped disc.
