抄録
Excess pressure drops in a flow through small apertures are experimentally investigated for various kinds of liquid and the following three types are found according to the kind of liquid : non-dimensionalized excess pressure drops at Reynolds numbers of magnitudes about 10 have (1) nearly the same values as the theoretical ones of Stokes flow (liquid paraffin and butanol), (2) higher values than the theoretical ones of Stokes flow, but they are correlated with Reynolds numbers regardless of the dimension of orifices used (ethanol and carbon tetrachloride), and (3) higher values than the theoretical ones of Stoke flow, and they do not correlate with Reynolds numbers (water), increasing with increase in orifice diameter at the same Reynolds number. It is shown that the non-dimensionalized excess pressure drops of water have some correlation with a dimensionless number V(λ/ν)1/2, where V is the mean velocity through an aperture, λ is the relaxation time of water and ν is the kinematic viscosity.
