- Joined
- Dec 26, 2020
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SolarYellow presented a good explanation of coning. The rockets fins are the strong corrective force. I'm looking at base drag is a possible resonant damping coefficient. The low-pressure region behind the vehicle dampens the overcorrection of the fins. Even when the Input frequency/Natural frequency =1. It's a theory that needs further work.
It started as a project to study launch exhaust flow patterns of finless cone and pyramid rockets when launched close to a flat plate flame deflector producing a low-pressure venturi effect region. It morphed into a base drag pressure measurement study of large diameter single engine rockets.
The limited data I've collected is trending to greater dampening after engine burnout.
I took a flight dynamics class long ago and I assume the rules haven’t changed…although I expect the experience base has grown some.
Which is to say I can see how the low pressure area at the base of a rocket in flight might dampen the pendulum but not effect spin (to use SolarYellow’s excellent top level description).
But what are the aerodynamics that are absorbing that energy? If the vehicle swings a few degrees to one side, does not the low pressure area at the base follow? Is there some time constant to that following that serves to dampen the swing? Or?
Bill