Lycopodium spores with diameter 4.2 µm have a sedimentation velocity in air of 0.50 mm s^−1. Estimate their drag coefficient.

Question

Lycopodium spores with diameter 4.2 µm have a sedimentation velocity in air of 0.50 mm [latex]s^{-1}[/latex]. Estimate their drag coefficient.

Accepted Answer

As [latex] Re_{p} [/latex] is small ([latex] Re_{p} = 0.5 imes 10^{-3} imes 4.2 imes 10^{-6} / 15 imes 10^{-6} = 0.14 imes 10^{-3} [/latex]), use the relation [latex] c_{d} = 24 / Re_{p} = 171 [/latex].

Question 9.1: Lycopodium spores with diameter 4.2 µm have a sedimentation ...