Flow pattern dynamics in convecting liquid helium.
We present experimental data which correlate thermal measurements and flow visualization in convecting liquid 4He. For a small range R(C)<R<R1 of the Rayleigh number R above the convection threshold value R(C) a robust stationary pattern is observed. This pattern exhibits periodic pulsation when R>R1, generating thermal oscillations as in earlier reports. At higher R values the time dependence becomes aperiodic with the surprising appearance of spiral-defect chaos at an aspect ratio smaller than has previously been reported.
Matley
R G
RG
Department of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom.
Wong
W Y
WY
Thurlow
M S
MS
Lucas
P G
PG
Lees
M J
MJ
Griffiths
O J
OJ
Woodcraft
A L
AL