A Computational Study to Predict Seakeeping Performance of a Surfaced Submarine in Irregular Waves

Abstract

Abstract In general, submarines are designed to optimize operation below the water surface because they spend most of their time in an underwater condition. However, the performance in free surface condition is also important because submarines face a variety of scenarios to complete operational missions and the free surface condition is unavoidable for port departure and arrival. In case of submarine, a numerical accuracy of potential theory for seakeeping analysis is excellent in submerged condition, but it is poor in free surface condition because of nonlinear effects near the free surface area. In this study, Star-CCM+ was used as a Reynolds-averaged Navier Stokes (RANS) solver to estimate the seakeeping performance of Canadian Victoria Class submarine in irregular waves, and the results were compared to those of model tests from a published paper. In addition, the potential theory code was also used for seakeeping performance to compare with Computational Fluid Dynamics (CFD) results. From the calculation results, the motion responses in irregular waves by using CFD showed similar trends to experimental results, while motion responses from potential code showed significantly larger values than experimental results. In conclusion, CFD simulations with irregular waves can be good solution to predict the seakeeping performance of submarines in free surface condition.