Numerical Prediction of the Powering Performance of a Car-Ferry in Irregular Waves for Safe Return to Port(SRtP)

Abstract

This paper considers a numerical assessment of the self-propulsion performance of a damaged ferry carrying cars in irregular waves. Computational fluid dynamics(CFD) simulations were performed to see whether the ferry complied with the Safe Return to Port (SRtP) regulations of Lloyd's register, which require that damaged passenger ships should be able to return to port with a speed of 6 knots (3.09 m/s) in Beaufort 8 sea conditions. Two situations were considered for the damaged conditions, i.e., 1) the portside propeller was blocked but the engine room was not flooded and 2) the portside propeller was blocked and one engine room was flooded. The self-propulsion results for the car ferry in intact condition and in the damaged conditions were assessed as follows. First, we validated that the portside propeller was blocked in calm water based on the available experimental results provided by KRISO. The active thrust of starboard propeller with the portside propeller blocked was calculated in Beaufort 8 sea conditions, and the results were compared with the experimental results provided by MARIN, and there was reasonable agreement. The thrust provided by the propeller and the brake horsepower (BHP) with one engine room flooded were compared with the values when the engine room was not flooded. The numerical results were compared with the maximum thrust of the propeller and the maximum brake horse power of the engine to determine whether the damaged car ferry could attain a speed of 6 knots(3.09 m/s).

Estimation of the Motion Performance of a Light Buoy Adopting Ecofriendly and Lightweight Materials in Waves

“…One of the methods to reduce wave reflection and computational cost while maintaining accuracy is the wave forcing method. As an inflow boundary condition, second-order Stokes wave theory was applied as the "velocity inlet" to express waves with the Euler-overlay method (EOM), which is a built-in forcing method of STAR-CCM+ [25,26]. In the overlay zone located from the inlet boundary to 2.4 m ahead of the buoy in the x-direction, analytic solutions and CFD solutions are gradually blended by applying source terms to VOF and momentum equations.…”

“…For outflow boundary, the "pressure outlet" boundary condition was used while adopting grid damping technique [27] to minimize the wave reflection at the boundary. For the side boundaries, the "symmetry plane" boundary condition was used [25,26]. Figure 15 shows the computational domain and boundary conditions for the motion simulation in regular waves using CFD.…”

A Numerical Study on the Performance of the 66k DWT Bulk Carrier in Regular and Irregular Waves

“…The frequency of wave spectrum equation was calculated, as shown in Equation (15). The wave height of the corresponding frequency can be obtained using Equation (16). Under the assumption of deep-water conditions, the wave number can be calculated as Equation (17), and the corresponding wavelength frequency can be calculated in the spectrum as Equation (18).…”