Measurement of Steady and Unsteady Duct Loads for Propeller 4381 at Crashback Conditions in the 36 in. Water Tunnel

摘要

Unsteady forces and moments were measured on a generic ducted propeller (P4381) under simulated crashback conditions in the 36 inch variable pressure water tunnel at the Naval Surface Warfare Center, Carderock Division. Both rotor and duct forces were measured using 6-component dynamometers in order to determine total propulsor forces. The duct forces were found to be responsible for the majority of the side force, exceeding the propeller side force by as much as three times. Little difference was noted between the vector sum of the rotor and stator force components due to phasing between the two components and the dominant forcing frequencies present in the signal. The unsteady rotor side forces were noted to be approximately 10% of the mean propulsor thrust, while the total side force (rotor plus stator) is approximately 30% of the rotor thrust.