Development of a Numerical-Semi Empirical Model to Estimate Hydrodynamic Derivatives of an AUV

Increased use of Autonomous Underwater Vehicles (AUVs) caused an increase in their design sensitivity. The subject of most of AUV design studies was on drag reduction, ease of handling and their stability. Adequate design and prediction of the behavior of these vehicles requires an accurate estimation of corresponding hydrodynamic derivative loads. In this study, Hydrodynamic derivatives of the AUV have been estimated using numerical and semi empirical methods. First, using a numerical method based on CFD, hydrodynamic derivatives related to the body of the Hydrolab500 have been estimated by applying pure heave and pure pitch oscillatory movements, and then, with the aid of semi empirical formulas, hydrodynamic derivative values of hydrofoils have been added. To validate the results, Planar Motion Mechanism (PMM) experimental test has been carried out using water tunnel tests. The validation results show that combining CFD method and semi empirical method is efficient in the calculation of hydrodynamic derivatives and is able to estimate these coefficients with reasonable accuracy. Using this method, the computational cost of detailed design has been reduced.