Rayleigh number calculus |
The Rayleigh number can be calculated with the formulas :
Ra=alpha*DT*g*a^3/(nu*K)
K=lambda/(ro*Cp)
Where the constants are, for water in standard scientific units :
alpha 0,00018
g 9,81
a 0,01
nu 0,000001
lambda 0,6
ro 998,2
Cp 4182
K 1,43731E-07
and a is the distance between the two walls.
If a=1cm, then :
DT Ra Epsilon
0,12 1474
0,13 1597
0,14 1720
0,15 1843
0,3 3686
1,2
0,5 6143
2,6
0,7 8600
4,0
2,3 28257 15,5
5,5 67570 38,6
more data here
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