Abstract:

ESDU 96031 provides guidance on the use of a module for Microsoft Excel for calculation of response of structures to vortex shedding. The basis of the calculation method is described in ESDU 96030. The program is applicable to parallel-sided, tapered and stepped sections with circular or regular polygonal cross sections of eight or more sides and smooth or rough surfaces (for surfaces with ancillaries such as ladders attached the method applies only if the ancillary is entirely in the main structure wake). Structures may be cantilevered or between end fixings, may be vertical, horizontal or inclined, and may or may not have strakes. They may be in a smooth or turbulent uniform or shear flow which may be normal to the structure or yawed. The program applies to natural wind (full scale), simulated wind (wind tunnel), and to internal flows in which the structure causes a blockage of less than 10 per cent. Example applications include stacks (chimneys) and process plant towers, lighting standards, elements of lattice structures and pipes spanning ducts. Several worked examples are included together with guidance on the required input data.