# Archived Linear Drag Coefficient

1. Mar 19, 2012

### Screwdriver

I'm trying to model the flight of a small spherical object (such as a ping-pong ball) through air at smallish velocities ($\approx 5{_{m/s}}$) with linear drag so that $F_{d}=-bv$. The problem is, I can't find a table of linear drag coefficients ($b$) anywhere; it's always just the normal drag coefficient $C_{d}$ which is for when the drag force is proportional to $v^2$. I don't think you can just use $C_{d}=b$ since they have different units.

However, I came across this, which I think is saying that $b=6\pi \mu R$, which would be good since I could look up $\mu$ from say, here. Does that seem like a good idea?

2. Feb 22, 2017

### Bernard of Go Mars

Well, 5m/s is not a speed at wich a linear drag occurs.
To be sure of it, see that general curve :
https://commons.wikimedia.org/wiki/File:CX_SPHERE.png

But if you realy wanted (I'm afraid it's too late) to calculate the flight of a sphere with a linear drag, I published recently these two tables of linear drag coefficients :
https://commons.wikimedia.org/wiki/...e_quelques_particules_en_Régime_de_Stokes.png
https://commons.wikimedia.org/wiki/File:Tableau_cx_lineaires_deuxieme.png

Friendly, Bernard of Go Mars