Fluid Dynamics, Calculating viscosity using damping coeffiecient

goblinhat

1. The problem statement, all variables and given/known data

Hello, I am doing a project which requires damping and have decided to use some viscous damping. It is simply on a hacksaw blade with a weight on the end. Therefore, other than just trial and error I would like to calculate the range of viscosities that may be useful for my damping.

I calcualted the damping coeffiecient c (using the spring coefficient and criticial damping) to be around 2.52. The spring constant being 8N/m and the mass approx 0.2kg. I plan to use a paddle and due to the design it will be around 5cm by 5cm in size and will be located roughly 10 to 15 cm from where it is secured. Also natural frequency is approx 1Hz if that is important.

I was hoping that someone may know some relevant equations to aquire the viscosity needed for critical damping - as i can't find this information anywhere. Any hep including useful links or equations is greatly appreciated.

2. Relevant equations

c=damping ratio*2*SQRT(km)---

3. The attempt at a solution

N/A