4 ms·
There will be a size below which fluid turbulence determines particle motion rather than particle density. This minimum size will increase for particles with ro
by ridgeguy 7y ago
There will be a size below which fluid turbulence determines particle motion rather than particle density. This minimum size will increase for particles with rough surfaces or high shape drag coefficients, or both.
In air, this size is ~ 10µm diameter [1]. In seawater, it should be considerably larger because Reynold's number.
[1] https://www.sciencedirect.com/topics/engineering/airborne-particle https://www.sciencedirect.com/topics/engineering/airborne-pa...
- gus_massa 7y agoIf it goes to the top or to the bottom is decided by the density. The difference between the density at the top of the ocean and at the bottom is very small 1.020 g/cm3 vs 1.050 g/cm3 . So it's very difficult to find a plastic that is in between https://en.wikipedia.org/wiki/Seawater#Thermophysical_properties_of_seawater https://en.wikipedia.org/wiki/Seawater#Thermophysical_proper... I agree that the size is important for the viscosity drag. This is the reason why the centrifuges are use in the lab to separate cells of blood or very small precipitates in solution. This can explain why a sibling comment says that suspending within 5 meters of the surface. If the plastic "wants" to float, but the waves mix the top few meters and it is so small that the drag don't allow it to reach the surface before the next wave mix it again. But to go to the bottom of the ocean, the plastic needs a higher density.