Pressure Field Around a Marine Propeller Operating in a Wake

Résumé du livre

An investigation was made on the effect of nonu iform inflo conditions on the vibra ory pressure generated by a marin prop ll r I a aly ing he pres ure signals which are associated with propeller thrust and torque, general xpressions are developed in terms of the harmonic constituents of the non-uniform inflow fi l . The analysis indicates that all possible combinatio of propeller-loading blade harmonics with those of the field-point function contribute to the pr ssure sign l. The effect of the nonuniformity of the inflow conditions persi t in the field and is felt at greater distances from the propeller plane han is e c e for uniform flow. At a distance of one prop ller radius the pressure a socia ed with th non-uniform conditions is almost 60% of the total. Two mat atical models were studied In both, the thrustproducing forces are assumed to be genera ed from a circular sector projection in the propeller plan, whereas th torque-producing forces are assu ed o be generated in t e first from a rectangul r pro ec io, i the s cond from a riangular projection, in t plan through t e propeller i an e line of mid-chord points. The study of both models indicates that the pres ure a sociated with torque is local in effect, being limited to the neighborhood of t prop ll r (Author.