Influence of the distance between vertical cylinders positioned in a row on the wind load on them

The silos and vertical cylindrical tanks of small volumes are often built in batteries, at short distances between them. As a result of their close location, the wind load on them increases. In the European standard EN 1991-1-4:2005+A1:2010 exists a methodology for determining this increase, which is dependent on the ratio a/d, where a is the distance between the facilities and d is their diameters. Unfortunately, this methodology is applicable for ratios a/d > 2.5. In cases where the values are smaller, the standard transfers to the national annexes. In the available to the author annexes, including the Bulgarian one, there is nothing on the subject. Moreover, the necessary information could not be found in the public scientific literature. Only in the Australian/New Zealand standard AS/NZS 1170.2:2011 are written some simple rules for closely spaced vessels. To fill this gap, multiple models of closely spaced cylindrical bodies has been created by the author. A computer fluid simulation (CFD) program is used for this purpose. In the present study, the bodies are arranged in one row and the wind blows them perpendicularly. Through these computer models is determined how the wind load changes due to their proximity. In contrast to what is stated in EN 1991-1-4:2005+A1:2010, the dependence is not linear, and the influence of the close arrangement of the bodies decays much faster. On the other hand, this influence should be considered at much greater distances between bodies than stated in AS/NZS 1170.2:2011.