AEROELASTIC ANALYSIS OF SPOILERS ON LOW-RISE BUILDINGS USING A FINITE ELEMENT MODEL FOR FLUID-STRUCTURE INTERACTION

Resumo

Low-rise buildings are highly susceptible to wind action due to the development of high suction pressures on their roofs, which result from vortices generated near the roof’s corners and edges. To mitigate wind loads on the roof structure, aerodynamic appendages may be incorporated into the building design. Previous work (see Bianchin and Braun, 2025) has shown that rigid spoilers can effectively reduce aerodynamic loading on the roofs of low-rise buildings. However, the feasibility of this load mitigation method depends on the spoiler dynamic stability and the strain/stress levels developed in the spoiler material. In this context, a fluid-structure interaction (FSI) model is proposed to numerically investigate the aeroelastic behavior and stress states induced by wind on aerodynamic appendages that are intended for future use in low-rise buildings to attenuate aerodynamic loading on roofs. In the present model, spoilers are considered elastic structures constituted of linear elastic material with geometrically nonlinear effects. The Finite Element Method (FEM) is adopted for spatial discretization using triangular shell elements (GPL_T9). The dynamic equilibrium equation is integrated over time using the implicit Newmark algorithm and the α-generalized method. The system of flow equations consists of the Navier-Stokes equations and the mass conservation equation for incompressible and isothermal flows, while Large Eddy Simulation (LES) is employed for turbulence modeling using a dynamic sub-grid approach. The numerical formulation for flow analysis is based on a semi-implicit Characteristic-Based Split (CBS) model within the Finite Element Method framework, where linear tetrahedra are used for spatial discretization. Fluid-structure coupling is achieved using a partitioned model, incorporating an arbitrary lagrangean-eulerian (ALE) formulation for flow kinematics and a numerical scheme for mesh motion. Test cases are simulated considering a boundary-layer wind profile and simple low-rise building models with rectangular spoilers positioned near the upwind roof edge. Results obtained here are compared with previous predictions using rigid spoilers. This study demonstrates the feasibility of using aerodynamic appendages for wind load attenuation in buildings, provided that they are not subject to excessive loading or aeroelastic phenomena.