Numerical study of drag force reduction methods in autonomous underwater vehicles

Today, the importance of reducing the drag force in subsurface vehicles has increased even more due to their use in the military, research and entertainment industries. In the leading research, the effect of various methods of reducing the friction drag, including the method of connecting the riblet to the body, covering the body, injecting air and heating the body, has been investigated on a subsurface vehicle. Validation of the results of the present numerical analysis was done by two solvers, Star CCM and Ansys Fluent, with experimental data. The combined shear stress transfer turbulence model was used to model the turbulent flow. The results of the study showed that the aforementioned methods in the best case reduced the drag force by 5.5%, 19.9%, 51.9% and 6.2%, respectively. All methods reduced the coefficient of friction drag. Also, the methods of coating and heating caused a slight decrease in the back pressure coefficient, while in the methods of connecting the riblet to the body and injecting air into the surrounding flow, this coefficient increased.