On September 21st 2020 Rubén Zorrilla has successfully defended his PhD Thesis titled "Towards the Virtual Wind Tunnel for Civil Engineering Applications" in the framework of Civil Engineering Programme. The thesis, which was carried out at the Technical University of Catalonia (UPC) under the supervision of Profs. Eugenio Oñate and Riccardo Rossi, has obtained a qualification of Excellent Cum Laude.
Rubén Zorrilla has been working as a researcher at CIMNE during his PhD studies and currently is Assistant Teacher at Technical University of Catalonia (BarcelonaTech).
Rubén Zorilla with his thesis directors. From left to right: Prof. Riccardo Rossi, Dr. Rubén Zorrilla and Prof. Eugenio Oñate
In this thesis, a numerical tool (the Virtual Wind Tunnel, VWT) is developed to solve problems that involve the flow of a fluid around a structure. Due to the limitations that traditional methods may have in this context, the VWT is based on the use of fixed mesh techniques (CutFEM type) combined with an implicit description of the embedded bodies. One of the main contributions of the thesis is the use of these fixed mesh methods to solve problems of light thin-walled structures.
Thus, two embedded formulations capable of representing the flow around a body with or without internal volume are proposed. The first one results in a simpler implementation as well as a lower computational cost but it can only represent a sliding behavior of the wall. The second removes this limitation by including an imposition by the Nitsche method of the Navier-slip condition, thus allowing any behavior to be modeled in the same way as a wall law would.
The range of applicability of the VWT includes the fluid-structure interaction problem (FSI). For this purpose, an improvement is proposed for the imposition of the boundary conditions of the mesh movement problem of the FM-ALE algorithm. Likewise, special emphasis is also placed on implementation, which has been conceived to be easily extensible to any other coupled problem. The validation of the technologies implemented in the VWT includes multiple theoretical cases as well as possible industrial applications. Among these, the FSI analysis of a 4-point tent during an episode of severe wind stands out as it demonstrates the achievement of the initial objective of the thesis.