1. Boundary conditions

The boundary name is just as shown in Figure 2. At the inlet of the 3D NWT, a specified boundary condition of fluid velocity **U** is set to *waveVelocity*, the boundary condition of the indicator phase function α is set to *waveAlpha*, and the boundary condition of the fluid pressure *p* is set to *zeroGradient*. At the top of the NWT, the velocity **U** is set to *pressureInletOutletVelocity*, which is a default boundary condition in OpenFOAM, the pressure *p* is set to *totalPressure*, and the phase function α is set to *inletOutlet*.

For the remaining parts of the NWT and the fixed suspending objects, the boundary conditions are considered as solid walls, where the fluid velocity **U** is set to a fixed value of zero, the fluid pressure *p* and the indicator phase function α are set to *zeroGradient*.
