1. Multi_Triangular Patch (MTP)

- The surface of body is represented as multi-triangular patch.

- The fine model of MTP is determined by the graphics options of body geometry.

- The coarsening factor can control the number of patches..

Figure 12.228: MTP type of Surface representation

2. Bounding Box

- The surface of body is represented as box geometry.

- The mass center and box center should be same.

Figure 12.229: BB type of Surface representation

1. Hydrostatic Force

-

- where, are the water density, gravitational acceleration, patch area and the distance of the patch centroid relative to the water surface. are the patch normal vector and vertical unit vector of the water reference frame. The gravity is always the opposite direction of the vertical direction.

Figure 12.230: Diagram of hydrostatic force

2. Hydrodynamic Force

- The relative velocity of patch centroid

- The normal pressure is computed from the fluid mass density and relative velocity.

, when

- The shear pressure is computed from the shear viscosity coefficient and relative

tangential velocity