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Laser Doppler velocimeter measurements of thermal counterflow jet in He II

✍ Scribed by M. Murakami; T. Yamazaki; H. Nakai

Publisher
Elsevier Science
Year
1989
Tongue
English
Weight
458 KB
Volume
29
Category
Article
ISSN
0011-2275

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✦ Synopsis

A thermal counterflow jet in stationary superfluid helium (He II) has been investigated using a laser Doppler velocimeter (LDV) with H2-D 2 solid particles as tracer elements in the flow.

The average normal fluid velocity measured with the LDV agrees well with a simple theoretical prediction below the condition of subcritical heating, where the velocity is small. For high velocities the measured velocity is less than that predicted theoretically. High resolution LDV data show the existence of regular oscillations in the velocity, superposed on a laminar base flow. The velocity oscillation is found to result from the second sound Helmholtz oscillation in the jet chamber. Supercritical heating generates quite a turbulent jet, in which the fluid dynamic behaviour seems very similar to that for fully developed turbulent jets in normal viscous fluids.

πŸ“œ SIMILAR VOLUMES

Flow structure of thermal counterflow je
Flow structure of thermal counterflow jet in He II
✍ A. Nakano; M. Murakami; K. Kunisada πŸ“‚ Article πŸ“… 1994 πŸ› Elsevier Science 🌐 English βš– 390 KB

The flow structure of a thermal counterflow jet is investigated by direct measurement of the normal fluid velocity with a laser Doppler velocimeter (LDV). The temporal and spatial variation of the normal fluid velocity is measured to investigate the detailed properties of a He II thermal counterflow

Flow visualization study of thermal coun
Flow visualization study of thermal counterflow jet in He II
✍ M. Murakami; N. Ichikawa πŸ“‚ Article πŸ“… 1989 πŸ› Elsevier Science 🌐 English βš– 551 KB

A method of flow visualization in superfluid helium has been developed by the use of solid H2-D 2 particles and hollow glass spheres as neutrally buoyant tracers to follow the normal component flow. It is applied to the study of a thermal counterflow jet based on pattern recognition of jet profiles

Velocity measurement of He II thermal co
Velocity measurement of He II thermal counterflow jet accompanied by second sound Helmholtz oscillation
✍ A. Nakano; M. Murakami πŸ“‚ Article πŸ“… 1994 πŸ› Elsevier Science 🌐 English βš– 608 KB

A laser Doppler velocimeter (LDV) is applied to the measurement of a thermal counterflow jet in He I1. It is capable of direct measurement of the normal fluid velocity. Detailed analysis of the velocity measurement results suggests that the normal fluid component entrains the surrounding superfluid