  Using computations of three-dimensional magnetohydrodynamic (MHD) turbulence
with a Taylor-Green flow, whose inherent time-independent symmetries are
implemented numerically, and in the absence of either a forcing function or an
imposed uniform magnetic field, we show that three different inertial ranges
for the energy spectrum may emerge for three different initial magnetic fields,
the selecting parameter being the ratio of the Alfven to the eddy turnover
time. Equivalent computational grids range from 128^3 to 2048^3 points with a
unit magnetic Prandtl number and a Taylor Reynolds number of up to 1500 at the
peak of dissipation. We also show convergence of our results with Reynolds
number. Our study is consistent with previous findings of a variety of energy
spectra in MHD turbulence by studies performed in the presence of both a
forcing term with a given correlation time and a strong, uniform magnetic
field. In contrast to the previous studies, however, the ratio of
characteristic time scales here can only be ascribed to the intrinsic nonlinear
dynamics of the flows under study.
