Measurement of Multiple Blade Rate Unsteady Propeller Forces
DAVID TAYLOR RESEARCH CENTER BETHESDA MD
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An experimental investigation of unsteady propeller forces was conducted using model propellers operating in idealized axial wakes. Three- bladed propellers were operated behind 3-, 6-, 9- and 12-cycle wake screens generating blade rate and multiple axial wake inflow harmonics. The axial wake distributions were measured using a Pitot tube. Unsteady propeller bearing thrust and torque were measured with an unsteady force dynamometer. Measurements were compared to calculations using unsteady propeller lifting surface theory. Also, Laser Doppler Velocimetry LDV was used to measure the unsteady flow field about the propeller. LDV measurements were used to evaluate the effect of the propeller on the incoming wake. Keywords Marine propellers Unsteady loads Bearing forces Model tests Propeller blades.
- Marine Engineering
- Fluid Mechanics