Superfluid Helium in Three-Dimensional Counterflow Differs Strongly from Classical Flows: Anisotropy on Small Scales

Area of Science:

• Fluid dynamics
• Quantum turbulence
• Condensed matter physics

Background:

• Classical turbulence typically becomes more isotropic and homogeneous at smaller scales.
• Understanding the behavior of turbulence in quantum fluids like superfluid helium-4 is crucial for fundamental physics.

Purpose of the Study:

• To investigate the scale-dependent behavior of three-dimensional anisotropic turbulence in superfluid helium-4.
• To determine if superfluid turbulence follows classical scaling laws or exhibits unique quantum phenomena.

Main Methods:

• Simulations of superfluid helium-4 turbulence in a three-dimensional counterflow channel geometry.
• Theoretical analysis to explain the observed anisotropic behavior.
• Comparison with established models of classical turbulence.

Main Results:

• Superfluid helium-4 turbulence in a 3D counterflow channel becomes less isotropic as scales decrease.
• The flow transitions towards a quasi-two-dimensional state at smaller scales.
• This behavior is contrary to the trend observed in classical fluids.

Conclusions:

• The scale-dependent anisotropy in superfluid helium-4 turbulence is a unique quantum effect.
• Classical models of turbulence are not directly applicable to superfluid helium-4 under these conditions.
• The findings provide new insights into the fundamental nature of quantum turbulence.