Determination of Hydrodynamic Coefficients for Rotary Derivatives with CFD Simulation

Indonesia possesses rich natural resources, including extensive marine biodiversity and underwater infrastructure. To maximize its potential as a maritime nation, the development of underwater vehicles has emerged as a viable solution. In recent years, there has been significant growth in the development and use of these vehicles, particularly for exploring underwater environments. Hybrid Remotely Operated Vehicles (HROVs) combine the advantages of Autonomous Underwater Vehicles (AUVs) and Remotely Operated Vehicles (ROVs), offering versatile operational modes for industrial applications. UUV Segara Nauta (SN-01) is an HROV developed at the TKD Laboratory of FTK-ITS Surabaya. To ensure effective manoeuvering in various degrees of freedom, the motion abilities of HROVs are evaluated through manoeuver testing, which reveals the vehicle's motion characteristics and response to commands. These characteristics are represented by hydrodynamic coefficients derived from the forces and moments experienced by the vehicle, obtained through CFD numerical simulations. This study performs a virtual captive model test using the UUV Segara Nauta (SN-01) model to conduct rotating arm tests. The focus is on determining the linear hydrodynamic coefficients in the horizontal plane, specifically for sway and yaw motions. Test variations include different drift angles and radius values to assess the effects of lateral and angular velocities. The CFD simulation results, including force and moment values, are converted into non-dimensional values and analyzed using linear regression to obtain the hydrodynamic coefficients. These coefficients explain the model's behavior and underwater hydrodynamic performance, which is more responsive but tends to be unstable.