Weaving classical turbulence with quantum skeletons*

We construct classical fluid turbulent flow fields consisting of intertwined viscous vortex tubes whose centerlines are quantum vortex filaments. First, the homogeneous isotropic quantum turbulence is simulated using the vortex filament method. Then, we transform quantum vortex filaments into spline-based parametric equations. They serve as the centerlines of viscous vortex tubes. By precisely controlling the degree of entanglement, core size distribution, and internal twist of the vortex tubes, we can customize the generated turbulent field with different Reynolds numbers and helicities. The combination of the turbulence skeleton (represented by quantum vortex filaments) and the tunable vortex-tube thickness makes the constructed turbulent field satisfy a series of key statistics, e.g., the five-thirds scaling and bottleneck effect of the energy spectrum and negative skewness of the velocity fluctuation in classical turbulence. This elucidates the essential difference between structures/statistics in classical and quantum turbulence.