A CFD-based Methodology for Accurate Estimation of the Hydrodynamic Forces and Moments on an Explorer Class AUV

Accurate estimation of the hydrodynamic forces and moments acting on an Autonomous Underwater Vehicle (AUV) is essential for optimizing their motion behavior and developing effective control strategies. In the present study, these hydrodynamic forces and moments acting on an Explorer class AUV are predicted using the Computational Fluid Dynamics (CFD) and Semi-Empirical (SE) methods for various angles of attacks (AoA) and operational speeds. Validation is done by comparing the CFD and SE results for the benchmark DARPA SUBOFF submarine model with experimental results available in the literature. The research also evaluates the applicability of SE equations for two different bare hull configurations - Explorer AUV and the DARPA SUBOFF. By comparing CFD and SE results, the study assesses errors in SE estimates at various angles of attack (AoA) ranging from 0° to 30°. SE equations are known to be effective for axisymmetric bodies up to an AoA of 12°. Beyond this range, the accuracy of SE equations in predicting forces and moments remains unexplored and is a key investigation area in the present study. As SE methods do not provide expressions for fully appended configurations, the current study employs a component build-up approach, summing the semi-empirically obtained drag contributions from the hull and control planes for the Explorer AUV. These component build-up-based SE results are then compared with CFD outcomes to evaluate their accuracy for fully appended configurations of the Explorer AUV.