Oscillatory convection in a dilute /sup 3/He-superfluid /sup 4/He solution

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1984

OSTI ID:5411355

Maeno, Y

Convective instabilities in a rectangular, unity aspect ratio Rayleigh-Benard cell with a solution of 1.46% /sup 3/He in superfluid /sup 4/He were studied in The Prandtl number range of 0.045 approximately less than or equal to sigma approximately less than or equal to 0.15. The onset of stationary convection is much like that in a classical, one-component fluid. The oscillatory instability is studied by using an extremely sensitive local temperature probe. It is found that the total heat transport efficiency is suppressed by the oscillations in the entire range of Prandtl number studied. The local temperature probe indicates a striking difference in the oscillatory amplitude when the sense of rotation of the convective rolls is reversed. The magnitude of the convective velocity is deduced from both the initial slope of the Nusselt number near the onset of the stationary convection and the frequency of the oscillations. The temperature dependence of the convective velocity determined by these two methods agrees very well with each other. The observed behavior of the oscillatory frequency and onset condition support the theory of oscillatory convection for a classical, low-Prandtl-number, one-component fluid. It is found that the onset of oscillations can be treated analogously to a second order phase transition. The oscillatory temperature amplitude is interpreted as closely related to the square of the order parameter.

• Research Organization: California Univ., San Diego (USA)
• OSTI ID: 5411355
• Country of Publication: United States
• Language: English

Related Subjects

640450* -- Fluid Physics-- Superfluidity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CONVECTION
DISPERSIONS
ENERGY TRANSFER
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
HEAT TRANSFER
HELIUM 3
HELIUM 4
HELIUM ISOTOPES
INSTABILITY
ISOTOPES
LIGHT NUCLEI
MASS TRANSFER
MIXTURES
NUCLEI
OSCILLATIONS
PRANDTL NUMBER
SOLUTIONS
STABLE ISOTOPES
SUPERFLUIDITY