Operator- and template-based modeling of solid geometry for Isogeometric Analysis with application to Vertical Axis Wind Turbine simulation

This article describes a novel approach to modeling and storage of NURBS-based solid objects for Isogeometric Analysis. The proposed method is based on a procedural description of the modeling process. Creation of geometric objects as well as the steps of the modeling process are formulated as a list of simple commands. This provides an abstraction from the often times tedious manual specification of control point locations to create a given geometric object. This operator-based approach, in conjunction with the existing template-based geometry modeling methods, allows one to create complex and multi-level adaptive models. To illustrate our method, we construct the geometry of a Vertical Axis Wind Turbine (VAWT) that is suitable for isogeometric fluid and fluid-structure interaction analysis. A new template is proposed for modeling VAWTs together with a novel algorithm for constructing wind turbine airfoil profile B-Spline curves from point data. The resultant model has a compact representation that makes use of a small number of parameters. A preliminary aerodynamics simulation of a newly constructed VAWT model in 3D under realistic wind conditions and rotation speed is presented.