Superfluid high REynolds von Kármán experiment.

Area of Science:

• Fluid dynamics
• Turbulence research
• Cryogenic engineering

Background:

• The von Kármán vortex street is a fundamental phenomenon in fluid dynamics.
• Studying turbulence at high Reynolds numbers is crucial for understanding complex flow behaviors.
• Existing experimental facilities often have limitations in scale or achievable Reynolds numbers.

Purpose of the Study:

• To present the design and initial performance of the Superfluid High Reynolds von Kármán experiment facility.
• To enable the exploration of ultra-high Reynolds numbers (Rλ > 10000) and the dissipative scale in turbulent flows.
• To provide a versatile platform for studying gaseous and liquid helium flows from room temperature down to 1.6 K.

Main Methods:

• Utilizing a high cooling power refrigerator (400 W at 1.8 K) for cryogenic operation.
• Generating von Kármán flow in a large-diameter (0.78 m) experimental setup with counter-rotating or co-rotating disks.
• Employing calorimetric measurements for dissipation, torque, and velocity measurements, alongside micro-Pitot and hot-wire anemometry for local flow characterization.

Main Results:

• Successful commissioning of the Superfluid High Reynolds von Kármán experiment facility.
• Demonstration of its capability to achieve ultra-high Reynolds numbers.
• Initial measurements of global flow behavior, including dissipation and torque, have been obtained.

Conclusions:

• The Superfluid High Reynolds von Kármán experiment facility is a significant advancement for turbulence research.
• The apparatus is capable of producing and measuring high Reynolds number flows relevant to various scientific and engineering applications.
• Further studies will benefit from the facility's unique capabilities for detailed flow analysis.