Numerical Investigation of Wind Induced Ovalling Vibrations in Silo Groups

Wind induced ovalling vibrations were observed during a storm in October 2002 on several empty silos of a closely spaced group consisting of 8 by 5 thin-walled silos in the port of Antwerp (Belgium). In the present study, it is investigated if the observed ovalling oscillations can be numerically predicted. To this end, the silo structures are modeled using a finite element (FE) model and the wind flow around a single silo is investigated using 3D computational fluid dynamics (CFD) simulations. A wind tunnel experiment was set up to validate the CFD simulations. To explain the onset of the wind induced ovalling vibrations, the interaction of the wind field with the structural vibrations has to be taken into account. Therefore, the complex interplay of both fields is investigated with both one-way and two-way coupling simulations. It is interesting to compare the results of both coupling approaches to assess the necessity of performing the computationally much more time-consuming two-way coupling simulations. It is found in both coupling approaches that the mode shapes with the lowest natural frequencies are excited dynamically. The results in the one-way coupling simulations differ however from those in the two-way coupling, demonstrating the importance of performing fully coupled simulations for suchlike aeroelastic problems. J. Hillewaere, J. Degroote, A. Rezayat, S. Vanlanduit, G. Lombaert, J. Vierendeels and G. Degrande