Aerodynamic study of flow past autonomous underwater vehicle at varying angles of attack.

When an autonomous underwater vehicle (AUV) sails beneath the water surface, the impact of various forces on the AUV's hydrodynamic performance is one of the key factors to be considered. A computational fluid dynamics (CFD) method is employed to numerically study and examine the parameters that effect hydrodynamic performance of an axisymmetric AUV travelling under water. The effects of flow on the AUV are quantified for various Reynolds numbers and submerged depths. It is assumed from past studies that the flow has a considerable impact on the AUV's lift & drag fluctuations, and the overall drag force increases with depth level and maneuvering becomes tough. This work focuses on study of flow past AUV where flow parameters like changing velocities, pressures and turbulence kinetic energies are studied. The analysis is carried out for AUV's at different angles of attack to study the required flow effects. The flow parameters like lift, drag, moment forces are evaluated to estimate the performance of the vehicle. The results obtained are in accordance with theory of aerodynamics where lift and drag forces are increasing with increase in angle of attack (AOA) from 00 to 100. The effect of aerodynamic stall is observed on further rise in AOA. Higher slope for lift coefficient is observed in comparison with that of drag coefficient. [ABSTRACT FROM AUTHOR]