## Calculating Drag Force due to air on a Pedestal Fan blade

I am doing a project where in a pedestal fan is alternatively powered using a flywheel. The flywheel is brought to some initial angular velocity by the electric motor. Now, if the power goes off, the fan blades would be coupled to the flywheel and it continues to rotate for the next 10 minutes.

After the power goes off, we have considered that

Energy-flywheel + Energy-fan = ∫ (Torque-drag force * ω -fan) dt

I'm having trouble calculating the torque due to the drag force and how to geometrically simplify the fan blades.

Any solution would be very much helpful.
 PhysOrg.com physics news on PhysOrg.com >> Is there an invisible tug-of-war behind bad hearts and power outages?>> Penetrating the quantum nature of magnetism>> Rethinking the universe: Groundbreaking theory proposed in 1997 suggests a 'multiverse'
 Mentor Welcome to PF! Why don't you just measure the electrical input to the fan?
 Yes, but that would give me the power consumed at some constant fan speed( during operation). When my flywheel is engaged, the rpm keeps on reducing and is a function of time. If I know how the drag force is related to angular velocity and how much torque is generated, I would then be able to solve.

## Calculating Drag Force due to air on a Pedestal Fan blade

Any idea about drag force, Russ?

Mentor
 Quote by Kaycee92 Yes, but that would give me the power consumed at some constant fan speed( during operation). When my flywheel is engaged, the rpm keeps on reducing and is a function of time.
Well, once you have the peak, you can use the fan affinity laws to calculate the power at any rpm. Basically, power is a cube function of rpm.

 Similar discussions for: Calculating Drag Force due to air on a Pedestal Fan blade Thread Forum Replies Mechanical Engineering 0 Introductory Physics Homework 5 Engineering, Comp Sci, & Technology Homework 1 Advanced Physics Homework 1 Introductory Physics Homework 1