In a 20483 simulation of quantum turbulence within the Gross-Pitaevskii equation, it is demonstrated that the large-scale motions have a classical Kolmogorov-1941 energy spectrum E(k)¿k-5/3, followed by an energy accumulation with E(k)¿ const at k about the reciprocal mean intervortex distance. This behavior was predicted by the L'vov-Nazarenko-Rudenko bottleneck model of gradual eddy-wave crossover [ L’vov, Nazarenko and Rudenko J. Low Temp. Phys. 153 140 (2008)], further developed in the paper.