Numerical Prediction of Self-propulsion Point of AUV with a Discretized Propeller and MFR Method

It is important to determine the self-propulsion point for marine vehicles to evaluate the approaching velocity output from a determined propeller. A method is presented that significantly reduces the computational cost by coupling a discretized propeller with a MFR (Multiple Frames of Reference) method for evaluation of the propulsion factors of AUV (Autonomous Underwater Vehicle). The predicted approaching velocity in this study was approximately 2.8% lower than the design value of 1.0 m/s obtained using nominal wake fraction, which can be attributed to increased energy dissipation for the water at the wake caused by the propeller. The effective wake fraction was 0.303 and the thrust deduction was 0.163.Vortex pairing was found at the blade tip and developed downstream of the propeller. In addition, the hull and tail-planes were beneficial for improving the thrust of the propeller. The proposed method is a viable option to validate fluid dynamics analyses of the unsteady motion of self-propelled marine vehicles simulated with physics-based methods, particularly for cases which have a shortage of experimental data.