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The stresses produced by magnetorotational turbulence can provide effectiveangular momentum transport in accretion disks. However, questions remain aboutthe ability of simulated disks to reproduce observationally inferredstress-to-gas-pressure ratios. In this paper we present a set of highresolution global magnetohydrodynamic disk simulations which are initialisedwith different field configurations: purely toroidal, vertical field lines, andnested poloidal loops. A mass source term is included which allows the totaldisk mass to equilibrate in simulations with long run times, and also enablesthe impact of rapid mass injection to be explored. Notably different levels ofangular momentum transport are observed during the early-time transient diskevolution. However, given sufficient time to relax, the different models evolveto a statistically similar quasi-steady state with a stress-to-gas-pressureratio, $\alpha \sim 0.032-0.036$.  The indication from our results is that {\it steady, isolated} disks may beunable to maintain a large-scale magnetic field or produce values for thestress-to-gas-pressure ratio implied by some observations. Supplementarysimulations exploring the influence of trapping magnetic field, injectingvertical field, and rapidly injecting additional mass into the disk show thatlarge stresses ($\alpha \sim 0.1-0.25$) can be induced by these mechanisms. Thesimulations highlight the common late-time evolution and characteristics ofturbulent disks for which the magnetic field is allowed to evolve freely. Ifthe boundaries of the disk, the rate of injection of magnetic field, or therate of mass replenishment are modified to mimic astrophysical disks, markedlydifferent disk evolution occurs.

Global simulations of magnetorotational turbulence III: influence of field configuration and mass injection