Unsteady Reynolds averaged Navier-Stokes simulation of the post-critical flow around a closely spaced group of silos

During a storm in October 2002, wind induced ovalling oscillations were observed on several empty silos of a closely spaced group of 8 by 5 silos in the port of Antwerp (Belgium). Present day standards describe only basic wind load cases, unable to explain this ovalling phenomenon. In order to improve the design of engineering structures with cylinders placed in groups, a thorough understanding of the fluid flow around such groups is required. 2D unsteady Reynolds averaged Navier-Stokes (URANS) equations using Menter's shear stress transport turbulence model were performed, considering the wind flow around the rectangular group for a range of angles of incidence (0° < a < 90°). The 2D highly turbulent post-critical flow (Re = 1.24 × 107) around a single cylinder was computed to elucidate the influence of the applied turbulence model and to validate the spatial and temporal discretization. Similarities of the flow regime around and within the present silo group and the flow around rectangular cylinders and the flow within tube arrays (e.g. heat exchangers) respectively are discussed to qualitatively assess the results of the simulations. Static and dynamic pressure loadings on separate silos of the group are studied to explain the existence and location of wind induced vibrations in closely spaced silo groups. It is found that ovalling oscillations in the third and fourth ovalling eigenmodes can be excited by dynamic pressure fluctuations at the lee side of the group, corresponding with the visually observed vibrations in 2002.

ISBN:978-90-760-1931-4

Publication year:2011

BOF-keylabel:yes

IOF-keylabel:yes

Authors from:Higher Education

Accessibility:Open