The discussion revolves around the conditions under which Brownian motion can suspend larger particles in a denser fluid, particularly in the context of ferrofluids. Participants explore the relationship between thermal energy, particle mass, and fluid viscosity, as well as the implications of different fluid types on particle suspension.
The discussion contains multiple competing views and remains unresolved regarding the maximum size of particles that can be suspended by Brownian motion in different fluids.
Participants acknowledge that there may be misconceptions about the underlying physics, and the discussion highlights the complexity of the interactions between particle size, fluid density, and thermal energy.
mpelaez83 said:The response is: kT>mgd, where kT is thermal energy, m the mass of the particle, g is gravity and s is the particle typical size. When thermal energy is smaller sedimentation will occur.
Sorry but what units were you're original equation in, I assumed it was jules> kg* 9.82* surface area in m^2mpelaez83 said:You actually account for that through viscosity in some way. The carrier fluid as you call it is accountef by a viscosity and a temperature, the system temperature
Is kT the energy of one carrier fluid atom or the energy of the system?mpelaez83 said:g has units of m/s^2, d is in meters and m is in kg. Then you get joules.