Fluid-Structure Interaction (TYPE 1 Interface)

TYPE1 interface is used to model fluid-structure interactions, as shown in Figure 1.

This interface allows Lagrangian elements (structure) to interact with ALE (Arbitrary Lagrangian Eulerian) elements, which model a viscous fluid. Full slip conditions are applied at the boundary between the two domains.

The acceleration of the Lagrange node is computed by:(1)

{\vec{γ}}_{i} = \frac{{\vec{F}}_{i} + \vec{F} {}_{a}}{m {}_{i}+ m_{a}}

The acceleration of the ALE node is computed by:(2)

{\vec{γ}}_{a} = \frac{\vec{F} {}_{a}}{m_{a}}

The grid velocity of the ALE node is equal to the material velocity of the Lagrange node:(3)

{\vec{w}}_{a} = {\vec{v}}_{i}

The normal material velocities of Lagrange and ALE nodes are equal. Therefore:(4)

{\vec{v}}_{a} \cdot \vec{n} = {\vec{v}}_{i} \cdot \vec{n}