Evaluation of submarine motions under irregular ocean waves by panel method

1485-1495This paper utilizes the Panel method to evaluate the effect of submerged depth in ocean waves on submarine motions. At the depth called the "wave base", the effects become so small that motions are almost negligible. The present research aims at recommending a safe depth for calm and stable motions of a submarine. Depth of λ/2 could be considered as an absolutely calm depth but a depth of 0.1λ is recommended as an operationally safe and approximately calm depth for submarines. To achieve the objectives of the study, a naval submarine was analyzed at some depths accompanied by regular surface wave. By increasing the depth, the reductions in submarine motions are evaluated. The obtained results from the study might have beneficial outcomes for AUVs, and research in submersibles and naval submarines. As mentioned, the analysis is performed by Panel method and the results are compared with those of a CFD method

Effective depth of regular wave on submerged submarine

1476-1484This paper evaluates the effective depth of waves on the submarine at the depth of water. Ocean surface wave has huge energy that causes dynamic variations on the floating and submerged bodies. Water wave is an orbital wave in which particles move in orbital path. These waves transmit energy along interface between two fluids of different densities. Circular orbital motion dies out quickly below the surface. At some depth below the surface, the circular orbits become so small that the movement is negligible. This depth is called the Wave Base. The decrease of orbital motion with depth has many practical applications. For instance, submarines can avoid large ocean waves simply by submerging below the wave base. This paper is aimed to recommend a safe depth for calm and stable movement of a submarine. This safe depth is not equal to wave base necessarily. For this study, a torpedo-shaped submersible is analyzed in several depths accompanied by regular surface wave. By increasing the depth, the reduction of submarine movements is evaluated. The results of this research can be used for AUVs, research submersibles and submarines. This analysis is performed by CFD tools of Flow-3D (V.10) software based on solving the RANS equations and VOF method