CFD Prediction of the Asymmetrical Shaft Unbalance During Ship Maneuvers

Description

Abstract. The paper explores the accuracy of a low-cost CFD based approach to evaluate the propeller load variation experienced during manoeuvring conditions. The proposed procedure is based on the inclusion, in the ship hydrodynamic analyses by RANS, of the propeller effect through a body-force approach calibrated on BEM calculation to realize a computationally efficient method. Numerical results have been compared with the literature available experimental data performed on the well-known DTMB5415 benchmark test case, where the thrusts experienced by both of her propellers during dedicated Captive Model Tests were recorded. Both pure drift and pure yaw tests have been considered in the numerical campaign to cover the entire kinematic conditions involved during standard IMO manoeuvres. To prove the effectiveness of the method, also a severe turning circle condition is evaluated. The comparison shows the maturity of these numerical calculations, even if based on a simplified approach, to correctly evaluate the propeller unbalance, opening the way to the application of the proposed method to investigate the causes of load variations in manoeuvre conditions and directly in manoeuvre simulations.

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