This chapter presents the theoretical basis of the linear and nonlinear elasticity structural model, which can be used to perform a flow analysis involving the prediction of stresses in a solid affected by a fluid flow. This feature is available for 2D planar and 3D meshes, but not for 2D axisymmetric meshes. In terms of physics, the feature is limited to linear isothermal and isotropic elasticity.

Although solving an elastic case on its own can be interesting, the real added value of the structural model is the ability to perform a fluid-structure interaction (FSI) simulation completely within a Fluent session. This is referred to as "intrinsic FSI", as all of the structural calculations are performed by Fluent; note that you can also use extrinsic solvers for FSI problems, incorporating the structural data into your Fluent fluid simulation through mapping or system coupling. The flow fields will apply forces on the interface boundary with the solid, which will deform; the resulting displacements of the solid domain will in turn lead to a deformation of the fluid domain.

The problem of linear or nonlinear elasticity is of the elliptic type, that is, the behavior is mainly dictated by boundary values (instead of initial values). Therefore, it is rather natural to use a finite element method for solving the stress and deformations in the solid body. On the fluid side of the FSI boundary, the physics is often dictated by transport (at least when the Reynolds number is sufficiently large), and so a finite volume method is appropriate. The art consists of establishing a communication between both of these regions / methods.

For information about using the structural model and simulation setup, see Modeling Fluid-Structure Interaction (FSI) Within Fluent in the User's Guide.