  We perform numerical simulation of quantum turbulence at zero temperature
generated by an oscillating sphere. In this simulation, we injected vortices on
the sphere to generate turbulence. Although we prepare injected vortex loops of
identical length, they are extended by the oscillating sphere to form a tangle
through numerous reconnections. The resulting tangle around the sphere is
anisotropic and affected by the oscillation. The vortex tangle continues to
emit vortex loops, which leave the sphere. The statistics of emitted loops
differ significantly from those of the original injected vortices. First, the
sizes of the emitted loops are widely distributed, ranging from smaller to much
larger than the size of the initial injected loop. Second, the propagation
direction of the emitted loops exhibits anisotropy: Small loops move away
almost isotropically but large ones do so anisotropically along the oscillation
direction of the sphere. Thus, the oscillating object stirs the initial
injected vortices to reproduce a group of vortices with different statistics.
Such physics is compared with the experiments of vibrating objects.
