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```5) is measured and correlated with viscosity. The Stormer formula is
/( )t A W Bµ= −
where A and B are constants which are determined by calibrating the device with a known
fluid. Here are calibration data for a Stormer viscometer tested in glycerol, using a weight
of 50 N:
µ, kg/m·s: 0.23 0.34 0.57 0.84 1.15
t, sec: 15 23 38 56 77
60 Solutions Manual • Fluid Mechanics, Fifth Edition
(a) Find reasonable values of A and B to fit this calibration data. [Hint: The data are not
very sensitive to the value of B.] (b) A more viscous fluid is tested with a 100-N weight
and the measured time is 44 s. Estimate the viscosity of this fluid.
Solution: (a) The data fit well, with a standard deviation of about 0.17 s in the value of
t, to the values
A ≈ 3000 and B ≈ 3.5 Ans. (a)
(b) With a new fluid and a new weight, the values of A and B should nevertheless be
the same:
300044 ,
100 3.5
A
t s
W B N
µ µ
= ≈ =
− −
solve for

new fluid
kg
m s
µ ≈
⋅
1.42 Ans. (b)```