# Fluid mechanics navier stokes flow around geometry

by joshmccraney
Tags: flow, fluid, geometry, mechanics, navier, stokes
 PF Gold P: 1,510 That depends on the context. With a cylinder in a viscous flow, very low Reynolds number in regards to whether Stokes flow is valid is typically considered to be $Re \ll 1$. It doesn't really make sense to just ask what constitutes very low Reynolds number in a random situation since you aren't really specifying in that case what physical phenomenon you are hoping to capture or avoid. For example, in Stokes flow, very low Reynolds number represents the region where the assumptions used in deriving it are valid.