A software tool named “T4T” (Tools for Turbomachinery) has been developed for the parametric design of turbomachinery and wind turbine blades. The complete design procedure is object-oriented and parametric, providing the ability to the user to define various types of blades. It has been developed in QT C++, utilizing OpenCascade graphical and computational libraries. The software allows the user to design the outer surface either by specifying some physical parameters for each blade section, or by directly interpolating a surface through a cloud of points. The new/enhanced version of “T4T” software tool, introducing the definition of internal blade structure for wind turbines rotors, is fully parametric and customizable, allowing the user for defining the internal blade structure, including shear webs. The computational procedure finally produces compound solids, which can be further imported to mesh generation and analysis software through standard geometry exchange protocols, for cooperation with CFD and CSD solvers.

The development of an efficient partitioned FSI coupling scheme is reported in this paper, aimed to facilitate interaction between an open-source CSD software package and an in-house academic CFD code. The coupling procedure is based on Radial Basis Functions (RBFs) interpolation for both information transfer and mesh deformation, entailing no dependence on connectivities, and hence making it applicable to different type or even intersecting grids. However, the method calls for increased computational resources in its initial formulation; to alleviate this deficiency, appropriate acceleration techniques have been incorporated, namely the Partition of Unity (PoU) approach and a surface-point reduction scheme. The PoU approach was adopted in case of data transfer, localizing the interpolation process and therefore reducing the size of the coupling matrix. An alternative approach was applied to improve the efficiency of the mesh deformation procedure, based on the agglomeration of the flow/structure interface nodes used for the RBFs interpolation method. For the demonstration of the proposed scheme a static aeroelastic simulation of a real bridge model, during its construction phase, was performed. The extracted results exhibit its potential to encounter effectively such complicated test cases, in a computationally efficient way.

Abstract. In this work the development of a partitioned FSI coupling procedure is reported, aiming to facilitate interaction between an open-source CSD (Computational Structural Dynamics)