European High-Performance Infrastructures
in Turbulence

The underlying physics of both classical and quantum turbulent front and its propagation represents a largely open and challenging fluid dynamical problem. We suggest to shed light on how the turbulent front- vortex tangle - moves and behaves in various quantum flows of superfluid bosonic He-4 in the simplest flow geometry, the channel flow. This can be reached by a complementary experimental, numerical and analytical study of the turbulent vortex front propagation in superfluid He-4 in different two-fluid flows (pure superfluid-, co- and counter-flowing He-4) over a wide temperature region ranging from 2.1 K down to 1.3 K, allowing to deal with He-4 consisting either mainly of the viscous normal fluid component, or mainly of the inviscid superfluid component, including intermediate cases when densities of normal and superfluid components are comparable. The basic idea, partly borrowed from similar studies in superfluid fermionic He-3 (by Helsinki experimental group in collaboration with V. L’vov) is that the velocity of turbulent front propagation is controlled by the type of two-fluid flow as well as by the global energy and mechanical momentum balance and can be relatively simply measured by just a few (e.g., two or three) local probes such as nuclear magnetic resonance in He-3 or second sound attenuation in He-4.