Low Q Spin-up from Rest.
Final rept. 15 May 82-15 Dec 85,
YORK UNIV NORTH YORK (ONTARIO) DEPT OF EARTH AND ATMOSPHERIC SCIENCE
Pagination or Media Count:
Eigenfrequencies and decay rates of inertial waves have been measured for both Newtonian and non Newtonian fluids contained in a cylindrical cavity while the fluid spins up from rest. The waves were excited by precessing the lid of the container until resonance was reached and detected by measuring disturbance pressure differences while the waves decayed freely. Measurements extend from 0.5 spin up times to steady state and over a range of Reynolds numbers 100-45,000 for the Newtonian fluids with precession amplitudes in the range 0.006-0.0328 radians. Measured eigenfrequencies agree to within a few percent with those previously calculated. Decay rates compare less favorably because they are more difficult to measure experimentally and to calculate theoretically. New methods of analysis were developed to recover the eigenfrequencies and decay rates. Previously used iterative techniques were modified to allow for the removal of the effects of recording filters and also automate the procedures used made possible with improved estimates of errors. New results for non Newtonian fluids which show shear thickening are presented. These fluids have anomalous behavior in the dependence of eigenfrequency and decay rate on time since the containers rotation began compared to that of a Newtonian fluid.