Mario A. Aguirre López

Environmental engineering is increasingly relying on advanced numerical tools to address the complex challenges associated with energy efficiency, air quality, pollutant transport, and sustainable infrastructure design

The increasing complexity of tall buildings demands higher performance in serviceability and resilience, particularly regarding airflow control to reduce vibration-inducing forces. On the other hand, harnessing wind energy in suburban environments remains a challenge for sustainable city planning. This study examines airflow around a tall building designed for vertical wind farming, incorporating passive flow-control balconies and a roof-mounted horizontal-axis wind turbine (HAWT). Using 3D-resolved flow simulations, we analyse configurations with a 3-blade HAWT placed at varying heights and combined with different balcony types. The results show that turbine height has a stronger influence on rotational performance and near-wake dynamics than balcony geometry, while the mid-wake depends primarily on the building itself. We also find that shorter turbines reduce material and maintenance costs while maintaining similar power output at 30 rpm, whereas taller turbines offer only marginal safety improvements at roof level. Overall, the prototypes demonstrate the feasibility of combining facade roughness with on-site wind harvesting to maximise energy capture without duplicating infrastructure in suburban contexts.

Computer-Aided Design has been broadly used as an essential tool for engineers, architects, and designers, helping the user to model 2D or 3D objects, enabling the development, modification, and optimization of final products. We present a Graphical User Interface (GUI) to extract silhouettes of an object from three images. After extraction, they are stored in an ordered array, in full or optimized versions, with a certain compression level. They are then extruded in each direction to build up the corresponding 3D object by intersection, which is stored in a mesh file; to be used as input for other purposes. The GUI is coded in Python with a user-friendly interface that calls FreeCAD for extrusion. Since the GUI was originally designed to generate objects for the study of fluid-structure interaction, our tested cases are vehicles. However, its potential use in other areas is discussed.

Silhouette extraction involves separating objects of interest from their background, which has several applications in image processing. Among the silhouette extraction techniques, contour tracing is commonly applied to images with a uniform background. This paper introduces a novel contribution to contour tracing techniques, utilizing the Wall-Follower Algorithm (WFA) to extract silhouettes with uniform backgrounds, or binary images. The algorithm is based on the analogy of a follower sequentially walking aside the external boundary of a wall, without separating a hand from it; then, the follower walks tagging silhouette pixels along the way until returning to the initial position and direction. Experimentation on vehicle technical drawings, satellite views of bodies of water and photographs of plants shows its effectiveness in producing high-quality silhouettes while showing some advantages over existing techniques. They include quickness in obtaining a solution, efficiency and ability to handle complex contours, and the option to simplify the results by reducing the percentage of saved points that trace the perimeter, based on object characteristics. The robustness of the algorithm suggests it as a promising alternative with diverse applications in image analysis, computer-aided design, and 3D object reconstruction, by extruding silhouettes, the latter being the main motivation for this contribution.