Numerical simulations for predicting wave force effects on dynamic and motion characteristics of blended winged-body underwater glider

Abstract

The Blended winged-body (BWB) shape of underwater glider (UG) has its unique advantages and gained remarkable attention in recent research. As BWB UG is autonomous underwater vehicle (AUV), the assessment of external disturbances and their effect on UG motion characteristics is of significant importance in order to accurately predict UG dynamics and navigation along the glide path. Being buoyancy driven slow speed vehicles, Waves play dominant role in disturbing UG dynamics near ocean surface, therefore better control systems and vehicle design can be achieved by studying of influence of wave parameters on the motion dynamics of the UG. Present work evaluates the underwater effects of wave forces on motion characteristics of BWB UG. The Wave forces acting on BWB UG are calculated in time domain by panel method. Series of simulations were performed considering Airy wave theory and head sea conditions. MATLAB curve fitting technique is used to derive analytical formulations for wave forces and moments on BWB UG obtained by panel method. The BWB hydrodynamics coefficients are calculated using Computational Fluid Dynamics (CFD). The fourth order Runge-Kutta method is used to solve motion dynamics model coupled with wave force analytical formulation in time domain. It is observed that the results of numerical simulations are reasonable and the wave force of different frequencies and amplitudes affect the UG stability and navigation along the glide path.