\(v=\frac{2}{9}\cdot \frac{(\rho _{p}-\rho _{f})gr^{2}}{\eta }\)

https://journals.physiology.org/doi/full/10.1152/physiol.00046.2018

I worked on some really crazy shit tonight... some of it was up for a few hours as I was working... but always careful not to give you what you need to create it or for the most part or even know wtf I'm talking about...