X-Nico

5 unusual facts about Reynolds number


Cell migration

Due to the highly viscous environment (low Reynolds number), cells need to permanently produce forces in order to move.

Lattice Boltzmann methods

LGA suffer from several innate defects for use in hydrodynamic simulations: lack of Galilean invariance for fast flows, statistical noise and poor Reynolds number scaling with lattice size.

It is therefore common to raise the lattice Mach number to something much larger than the real Mach number, and compensating for this by raising the viscosity as well in order to preserve the Reynolds number.

Seymour Narrows

Seymour Narrows is notable also because the flowing current can be sufficiently turbulent to realize a Reynolds number of about 10^9, i.e. one billion, which is possibly the largest Reynolds number regularly attained in natural water channels on Earth (the current speed is about 8 m/s, the nominal depth about 100 m).

Turbulent diffusion

In the past, laboratory efforts have used data from steady flow in streams or from fluids, that have a high Reynolds number, flowing through pipes, but it is difficult to obtain accurate data from these methods.


Sedimentation

For small enough particles (low Reynolds number), the drag force varies linearly with the terminal velocity, i.e., F {drag} = f v {term} (Stokes flow) where f depends only on the properties of the particle and the surrounding fluid.


see also