Calculating Drag Force and Spin for a Ping Pong Ball Launcher

[chris_tams]

Hi there. I'm at bath uni. Our group is building a ping pong ball launcher. Here are some issues we encountered.

If the ball is to drop vertically into a 40mm tube with air flowing at 6bar(does this mean anything?) will it drop in or will it blow back out.

Also I'm not to sure how to calculate the drag force on the TT ball through the air. I need to calculate its range and trajectory. Obviously this will change when spinning. Is it possible to take spinning into account on paper?

Is there a standard integral i need to calculate the drag at each velocity?

Any help will do.

Thanks

 

[Andrew Mason]

Hi there. I'm at bath uni. Our group is building a ping pong ball launcher. Here are some issues we encountered.

If the ball is to drop vertically into a 40mm tube with air flowing at 6bar(does this mean anything?) will it drop in or will it blow back out.

Also I'm not to sure how to calculate the drag force on the TT ball through the air. I need to calculate its range and trajectory. Obviously this will change when spinning. Is it possible to take spinning into account on paper?

Is there a standard integral i need to calculate the drag at each velocity?

A dynamic pressure of 6 bar is huge so I have no doubt the ping pong ball will blow back out. I think you could blow through the tube and blow the ball out. I don't see how you could calculate it on the information provided.

AM

 

[charng]

for reaching out. It sounds like you and your group are working on an interesting project. To answer your first question, if the air pressure is at 6bar, it is likely that the ping pong ball will be blown back out of the 40mm tube. The pressure is high enough to create a force that is stronger than the force of gravity pulling the ball down. To prevent this, you may need to adjust the pressure or the size of the tube to create a balance between the two forces.

To calculate the drag force on the ping pong ball, you can use the drag equation: Fd = 0.5 * Cd * ρ * V^2 * A, where Fd is the drag force, Cd is the drag coefficient, ρ is the density of air, V is the velocity, and A is the cross-sectional area of the ball. The drag coefficient can vary depending on the shape and surface of the ball, but for a smooth sphere, it is typically around 0.47. You can use this equation to calculate the drag force at different velocities and then integrate it to find the total drag force on the ball. To take into account the spinning of the ball, you can use the Magnus effect, which is the force that is created when a spinning object moves through a fluid. This can be a bit more complex to calculate, but there are resources available online that can help you with the equations and calculations.

I hope this helps. Best of luck with your project!