The data presented (used in conjunction with Reference 1 to account for free-end effects and shear flow) form the basis for estimating mean force coefficients acting on circular cylindrical structures of many types in a variety of conditions. The following data can be obtained from this data Item.

Purpose

The purpose of this Data Item is to provide data for estimating the mean forces induced by flow around a cylindrical structure of circular cross-section. Only single cylinders are considered in this Item; mean forces on cylinders in groups will be the subject of a separate Data Item. In the present context the data apply when the effect of the flow around the free end (or ends) can be ignored (e.g. for long cylinders). Reference 1 provides additional information in the form of correction factors which can be applied to these data to account for end effects and shear flow effects, such as those associated with cantilever structures in the non-uniform atmospheric wind.

The circular cylinder is one of the most commonly occurring shapes in engineering structures. Typical examples are chimney stacks, towers, storage tanks, silos, cables, pipe lines, space vehicles and missiles, and elements of structures such as lattice towers and off-shore structures. Other examples are pipes and struts inside ducts but in these cases the confinement effects due to the proximity of the duct walls must be taken into account (see ESDU 80024⁹). In many situations the overall response (mean and fluctuating) of the structure to the approaching flow, such as the atmospheric wind, is needed for design purposes. This Item provides data for estimating the mean components of loading. The fluctuating components, such as those arising from buffeting by a turbulent flow or from vortex shedding, must also be considered; ESDU 87035⁷ provides methods for estimating the maximum design loading due to buffeting by atmospheric turbulence (along the wind direction) and Reference 8 deals with the across-flow response due to vortex shedding.