Experimental and numerical investigation of water impact on air-launched AUVs

Air-launched autonomous underwater vehicles (AUVs) are subjected to huge impact loads in the early stage of water entry, which may cause structural damage or failure of electronic components, especially in the case of high speed water entry. Therefore, it is very imperative to carry out experimental and numerical research on the impact loads of air-launched AUVs. An experimental study of the water entry of air-launched AUVs with different launch velocities and angles was conducted using high-speed photography and sensing technology. The axial and radial accelerations of AUVs under different working conditions at the early stage of water entry were obtained. Furthermore, a coupled finite element technique and the smooth particle hydrodynamics method (FEM-SPH) is employed to model the water entry process of air-launched AUVs. Numerical simulation results such as the peak of impact acceleration were compared with the presented experiment results. The good agreement between the experimental results and the numerical simulation results revealed the capability and accuracy of the numerical algorithm in solving the problem of AUV water entry.