Influencia del movimiento relativo de un vector de cuatro cilindros independientes durante los fenómenos de interferencia por estela y proximidad

Laburpena

In the design of the PortaFira Hotel facade system (Toyo Ito, Barcelona); an experimental study of the relative movement between an array of four circular cylinders was completed to examine possible wake and proximity interference. The divergent character of this interference-induced instability is known to compromise structural integrity and, as such, must be considered early in the design stage. Currently, an evaluation may only be completed in a correctly configured wind tunnel study, in this case with a vector of four circular cylinders of diameter, D, of 110mm, and length, L, of 1340mm. The wind tunnel study of the PortaFira Hotel facade systems was examined by the Oritia & Boreas personnel in the University of Granada boundary layer wind tunnel, concluding with the design of a tuned mass damper (TMD) specific to the aerodynamic properties of the facade system. The flow around grouped bluff bodies (like a cylinder) is complex. When a cylinder is in close proximity to an adjacent cylinder and partially or completely submerged in its wake, phenomena known as proximity or wake interference may occur. In the case of the present study (L/D=1.91), the wake of the upstream cylinder may be interrupted and the dynamic response and vibration characteristics of the cylinders in the group are interrelated [Zdravkovich; 1977, 1987], forming mechanisms of mutual interference which are difficult to predict analytically. Given the technical complexity of the methodology, experimental studies of the phenomena are typically simplified to reduce the number of components and degrees of freedom of the experimental model. Few studies have been performed with two or more freely oscillating cylinders, which are however, the case of the majority of practical engineering problems. The experimental study was performed in the upstream section of the University of Granada wind tunnel. A specific test rig was designed and constructed for the study, which includes an independent elastic suspension system for each cylinder. The drag response was restricted to eliminate associated mechanical interference between bodies. Each cylinder could also be independently fixed, giving a total of eight freely oscillating/fixed test configurations. Analysis of the response between test configurations presents significant conclusions, revealing the relative movement of the group of cylinders is reduced if all cylinders are freely oscillating, analogous to an increase in damping and consequently, study results may be considered conservative if not included in the analysis.