On two-dimensional water-solid impact with VOF methods

Procedures are presented that allow an accurate treatment with the Volume of Fluid (VOF) method of the impact between an incompressible fluid and solid boundaries. The identification and correct handling of impact are made possible by the use of appropriate procedures for the treatment of fluid and obstacle cells along the solid boundaries. These procedures, first introduced in the context of marker and cell methods, are adapted and implemented here for VOF methods and their effectiveness is demonstrated. Also, intrinsic deficiencies which are specifically associated with VOF methods are addressed. The very high velocities, which are exhibited during impact by the classical VOF methods, are avoided by the use of special impact pressure boundary conditions. As a result, a more realistic impact pressure pulse is obtained. Numerical examples of a broken dam problem are used to illustrate the deficiencies of traditional VOF methods in simulating impact between water and a solid structure. Experimental and numerical results of flow over a containment dike are used to demonstrate the effectiveness of the improved VOF method.