De Marssumermolen, Marssum 57 cogs. This drives the "wallower" (31 cogs) at the top of the "upright shaft". At the bottom of the "upright shaft" there are two "crown wheels"' The upper "crown wheel", which has 17 cogs drives an Archimedes' screw. The axle of the Archimedes' screw is diameter and long. This screw is used to pump water into the polder. The lower "crown wheel", which has 43 cogs, drives a gearwheel with 38 cogs on the axle of an Archimedes' screw, which is used to drain the polder. The axle of the screw is diameter and long. The screw is diameter.
Archimedes number forced convection dominates. When the density difference is due to heat transfer (e.g. fluid being heated and causing a temperature difference between different parts of the fluid), then we may write where: Doing this gives the Grashof number, i.e. the Archimedes and Grashof numbers are equivalent but suited to describing situations where there is a material difference in density and heat transfer causes the density difference respectively. The Archimedes number is related to both the Richardson number and Reynolds number via Archimedes number In viscous fluid dynamics, the Archimedes number (Ar) (not to be confused with Archimedes' constant, π), named