Influence of the distance between in-line vertical cylinders on their wind loading

<jats:p>This paper is the latest in the author’s research on the influence of the distance between vertical cylindrical bodies on the wind load on them. This research was prompted by the lack of information on the subject, and such information is vitally needed, since technological facilities with small volumes, such as silos and vertical cylindrical tanks, are often built in batteries, at small distances between them. As a result of their close location, the wind load on them is different from that on single facilities.The current version of the European standard EN 1991-1-4:2005+A1:2010 describes a methodology for determining the increased wind load on bodies arranged in a row perpendicular to the air flow. This methodology depends on the ratio between the distance a between the facilities and their diameter d and is valid for ratios a/d &gt; 2,5. However, the standard does not contain any prescriptions on how to determine the wind influence for more closely spaced bodies and those arranged in-line. Despite an intensive search in the available scientific literature, the author was unable to find the information he needed. Only in the two editions of the Australian and New Zealand standard AS/NZS 1170.2 from 2011 and 2021 there are a few simple rules written down for closely spaced facilities. To fill this knowledge gap, in late 2023, the author began research on the subject. Using a computational fluid dynamics (CFD) program, he created multiple models of closely spaced cylindrical bodies that are blown by a wind flow. The first results obtained for the load on bodies that are arranged in a row perpendicular to the air flow are presented in a paper published in 2024. The results for the load on bodies arranged in a row whose axis is not perpendicular to the air flow should be published in the current 2026. The present paper is a natural continuation of the research and will present the results for the loading on in-line arranged bodies (where the wind flow is parallel to the row axis). The author hopes that this study will successfully bridge the remaining knowledge gaps on the topic.</jats:p>