Fluid-structure interaction with NURBS-based coupling
For engineers using CAD-based design, this method simplifies coupling of fluid and structural simulations by leveraging a shared spline geometry, but the work is incremental as it extends existing NURBS-based techniques.
The paper presents a method for fluid-structure interaction using a common NURBS interface, enabling direct transfer of quantities between structural and fluid solvers while allowing individual refinement levels. The approach combines isogeometric analysis on the structural side with NURBS-enhanced finite elements on the fluid side.
Engineering design via CAD software relies on Non-Uniform Rational B-Splines (NURBS) as a means for representing and communicating geometry. Therefore, in general, a NURBS description of a given design can be considered the exact description. The development of isogeometric methods has made the geometry available to analysis methods Hughes et al. (2005). Isogeometric analysis has been particularly successful in structural analysis; one reason being the wide-spread use of two-dimensional finite elements in this field. For fluid dynamics, where three-dimensional analysis is usually indispensable, isogeometric methods are more complicated, yet of course not impossible, to apply in a general fashion. This paper describes a method that enables the solution of fluid-structure interaction with a matching spline description of the interface. On the structural side, the spline is used in an isogeometric setting. On the fluid side, the same spline is used in the framework of a NURBS-enhanced finite element method (extension of Sevilla et al. (2011)). The coupling of the structural and the fluid solution is greatly facilitated by the common spline interface. The use of the identical spline representation for both sides permits a direct transfer of the necessary quantities, all the while still allowing an adjusted, individual refinement level for both sides.