Unsteady Force Measurement Using Small Piezoelectric End Sensors

Open Access
Author:
Goldschmidt, Margalit Zipora
Graduate Program:
Aerospace Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
August 07, 2014
Committee Members:
  • Michael Lester Jonson, Thesis Advisor
  • George A Lesieutre, Thesis Advisor
Keywords:
  • unsteady
  • piezoelectric
  • dynamometry
Abstract:
Most marine propellers operate in a nonuniform flow field. Understanding the unsteady lift generated on the propeller blades by these upstream wakes is important in order to reduce vibration and noise and therefore develop more efficient turbomachines. Currently, complex instrumentation involving unsteady dynamometry and pressure sensor arrays are utilized to characterize the unsteady pressures across propeller blades. New, simpler sensors have been designed to replace current instrumentation. These sensors take advantage of the oscillating nature of the unsteady lift, as at increasing inflow harmonics the rapidity of the unsteady lift fluctuations suggests that the lift nearly cancels out over the blade radius, and that the total unsteady force across a propeller blade can be found from parameters at the root and tip. These parameters were determined from an approximation provided by the Method of the Stationary Phase. Using this method, new sensors were designed and optimized to work universally. The newly designed sensors will be validated in a future experiment.