Yaw instabilities produced by rapidly rotating, highly viscous liquids
Abstract
A liquid-filled gyroscope was used to study the yaw instabilities for low Reynolds numbers. Control of physical variables produced a range in Reynolds number (Re) of 5 to 12 x 10 to the 3rd. The gyroscope is freely gimballed and spun at a constant rate by a dc motor. The logarithmic amplitude of the gyroscope motion grew linearly with time, and linear behavior was observed for precession angles smaller than 5 deg. The data suggested that the growth rates also varied linearly with the coning frequency, tau(R), of the liquid-solid parts. The strongest correlation for the amplitude growth rate of high viscosity liquids occurred for the product Re x tau(R). The experimental demonstration of growth rates proportional to the coning frequency is not consistent with the classical liquid-induced instability, which is based upon a resonant matching of a natural frequency of oscillation of the fluid and the coning frequency.
- Publication:
-
AIAA, Aerospace Sciences Meeting
- Pub Date:
- January 1981
- Bibcode:
- 1981aiaa.meetU....D
- Keywords:
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- Gyroscopic Stability;
- Liquid Filled Shells;
- Rotating Liquids;
- Viscous Fluids;
- Yaw;
- Flight Stability Tests;
- Reynolds Number;
- Instrumentation and Photography