Numerical study on Estimation of Hydrodynamic Force acting on Open-frame Underwater Vehicle

In this paper, the estimation accuracy of hydrodynamic force acting on the fuselage of an open frame type AUV by CFD analysis was investigated. The hydrodynamic force acting on the fuselage was examined in case that the fuselage is stationary state including oblique and trim angle and the forced oscillation state including pure heave and pure pitch motion. Using the result of computation of pure pitch motion, the hydrodynamic derivatives are calculated by using harmonic analysis. These results were compared with the measured values obtained by experiment in the circulating water channel at Tokyo University of Marine Science and Technology using the experimental model made from the same CAD data which used as the numerical model for CFD.From these results, the followings are revealed. The prediction accuracy of the hydrodynamic force is greatly affected by the computational domain, Spalart-Allmaras turbulence model and SST k-ω turbulence model have similar estimation accuracy for hydrodynamic force, There is a possibility that the flow prediction accuracy is insufficient inside the fuselage, the hydrodynamic force derivative calculated from the result of numerical PMM test can almost explain that of experimental PMM test.