Analysis of fluid flow and fluid-structure interaction in the framework of isogeometrically enriched finite elements

The isogeometric analysis (IGA) has found wide range applications in the area of computational modeling and analysis. Employing CAD entities (such as NURBS, T-Splines and others) as basis functions for finite elements, IGA has enriched the traditional finite element method with superior geometrical precision and higher solution accuracy. In this thesis, a numerical strategy to blend IGA within a classical finite element mesh representation, composed of Lagrange finite elements, is presented. Such an innovation is possible by employing the isogeometrically enriched finite elements, which act as an interface between the IGA elements and the Lagrange finite elements. Adopting this methodology leads to the localized IGA zone enrichment approach, where it is possible to model major part of the bulk domain with Lagrange finite elements, while IGA is performed only at regions where it may be critically beneficial. The strategy promises substantial benefits in terms of analysis accuracy and computational savings for problems involving fluid flow, where often the bulk domain is large but strong gradients are only present in the near boundary-surface region. This potential of the proposed strategy is demonstrated in this thesis by adopting the isogeometric enrichment strategy to several established numerical test cases involving laminar fluid flow and fluid-structure interaction