Prediction of ship-lock interaction by using a modified potential flow solver

Ship-lock interactions are very difficult to predict. The hydrodynamics of ships entering (or leaving) a lock is always accompanied with shallow water and bank effects. When a ship enters or leaves a lock with a closed end, a so-called piston effect will be provoked due to the translation waves trapped in the gap between the ship and the lock door. Meanwhile, as the water is accumulating or evacuating in a lock with closed end, a return flow will be generated. The nature of the complex hydrodynamics involved in ship-lock interactions have not been fully understood so far and it is very challenging to develop a mathematical model to predict ship hydrodynamics in a lock. In the 4th MASHCON, the author presented his original simulation results of the hydrodynamic forces on a ship when it entered a lock based on a potential flow solver MHydro. A very large discrepancy was found between the numerical results and experimental measurements. It was con-cluded that the potential flow theory failed to predict the hydrodynamic forces on a ship when it entered a lock. Over the past two years, the author has continuously worked on ship-to-lock problem and proposed amodified potential flow method by adding a proper return flow velocity to the boundary value problem. The results showed the modified method could predict the resistance and lateral forces very well. However, it failed to predict the yaw moment due to the flow separation at the lock entrance.