Chief Longwind Of The North
Certified/Certifiable
Any physicists out there? I have a of late witnessed a phenomenon that perplexes me. I believe it is related also to the way a Rapalla fishing lure works. Here's what I witnessed:
When lifting a thin, Styrofoam drinking cup (will hold twelve ounces of liquid) from a stack, often times, several will lift due to the partial vacuum between the cups. When I force the cup I'm grasping to release from the other cups, they fall back onto the stack. As they fall, they oscillate sideways at a particular frequency. I don't understand why, or how to determine the oscillating frequency.
I understand that as they fall, air is compressed and forced out of the underside of the cup, between the inside of the falling cups, and the outer surface of the stationary cups.
In the fishing lure, there is a blade on the leading edge of the lure that builds fluid pressure before it. The lure is forced to track sideways to release that pressure until the angular pressure on the side of the lure forces the lure to travel once more in a straight line behind the moving fishing line. It moves a fraction to far due probably to its sideways momentum, and then dumps pressure in the other direction, again moving sideways to the direction of travel until the water pressure on the lure side is greater than the pressure on the lip. The cycle repeats so long as the lure is dragged through the water.
I believe that the frequency of the lure oscillations is a function of the lip area compared to the area of the lure side. But for the life of me, I can't determine what would cause the oscillations in the cup.
Any ideas?
Just brain push-ups for the day.
Seeeeeeya; Chief Longwind of the North
When lifting a thin, Styrofoam drinking cup (will hold twelve ounces of liquid) from a stack, often times, several will lift due to the partial vacuum between the cups. When I force the cup I'm grasping to release from the other cups, they fall back onto the stack. As they fall, they oscillate sideways at a particular frequency. I don't understand why, or how to determine the oscillating frequency.
I understand that as they fall, air is compressed and forced out of the underside of the cup, between the inside of the falling cups, and the outer surface of the stationary cups.
In the fishing lure, there is a blade on the leading edge of the lure that builds fluid pressure before it. The lure is forced to track sideways to release that pressure until the angular pressure on the side of the lure forces the lure to travel once more in a straight line behind the moving fishing line. It moves a fraction to far due probably to its sideways momentum, and then dumps pressure in the other direction, again moving sideways to the direction of travel until the water pressure on the lure side is greater than the pressure on the lip. The cycle repeats so long as the lure is dragged through the water.
I believe that the frequency of the lure oscillations is a function of the lip area compared to the area of the lure side. But for the life of me, I can't determine what would cause the oscillations in the cup.
Any ideas?
Just brain push-ups for the day.
Seeeeeeya; Chief Longwind of the North