Numerical and experimental investigation of the hydrodynamic Lift and Drag coefficients of a solar-powered AUV in near-surface mode

To obtain the hydrodynamic forces acting on a solar-powered AUV, and to investigate the effects of the free surface, a model of this type of vessel was simulated in ANSYS FLUENT ۱۸ commercial software. To validate the data, a vessel with a scale of ۱: ۱ compatible with the installation of photovoltaic panels was built and tested in the towing tank of the National Iranian Marine Laboratory (NIMALA). The standard k-ε model and multi-block mesh were used to simulate the three-dimensional unsteady viscous flow around these cases: individual struts, the body without struts, and the body with struts. Three depth-to-diameter ratios ( h d =۳.۶ , ۴.۵ , ۵.۲ ) and six Froude numbers in the range of ۰.۰۶ ~  ۰.۳۵, equivalent to the Reynolds range ۲.۴×۱۰ ۰۵ to ۱.۴× ۱۰ ۰۶ , were used to obtain lift and drag coefficients. The findings of this study were used to create a solar AUV. The maximum percentage of struts contribution in the total resistance force is ۶۲ percent. The generated resistance effect, caused by struts and their attachment to the body, also plays a significant role. According to the current study data for the analyzed model, its maximum value is around ۴۱ percent.

Keywords:

solar AUV , hydrodynamic coefficients , CFD , towing tank