CFD_STRUCTURE_INTERACTION
CFD
Beta command
This command is in the beta stage and the format may change over time.
"Optional title"
coid, output
entype, enid, itype, $C_1$, $C_2$
Parameter definition
Description
This command is used to define the interaction between the CFD domain and overlapping Finite Elements. It is a a more flexible alterative to the coupling definition that can be made directly in CFD_DOMAIN.
The blocking coupling treats overlapped CFD cells as rigid boundaries for the gas flow. Pressure is transferred from the CFD domain to the Finite Element surfaces. Finite Element surfaces in motion excert positive or negative work on the local CFD cells, ensuring an accurate energy balance in the coupling interface.
The porous coupling allows the gas to dissipate through the overlapping Finite Element structure. The flow resistance is controlled with parameters $C_1$ and $C_2$. The resulting body load (force per unit volume) is defined as:
$\displaystyle{ \mathbf{f} = \rho_{CFD} \cdot (C_1 + C_2 \vert \mathbf{v}_{rel} \vert) \cdot \mathbf{v}_{rel} }$
where $\rho_{CFD}$ is the gas density and $\mathbf{v}_{rel}$ is the local relative velocity between the CFD cell and the overlapping element.
If output=1, then the file _cfd_face_data.k is output at termination time. This file contains an INITIAL_FACE_DATA command with information about the local gas pressure, temperature, density and local tangential flow velocity for all element faces in the coupling interface.
