This work presents a systematic study of numerical model parameters for slamming simulations of two-dimensional flat plates. The study showed that the use of structured meshes, turbulence modeling and the activation of compressibility model in air are important to simulate the cushioning effect caused by the air trapped between the plate and the water surface. Water compressibility seems not to be important for impacts at low velocities. Finally, a convergence study showed reasonable agreement when mesh and time step were simultaneously refined to keep a constant Courant number.