ESDU 96031:2010

INTRODUCTION

ESDU 96030⁶ describes the nature of the lateral
response to vortex shedding of structures of circular cross
section. It then develops a method for calculation of this response
together with the data required for its implementation. This method
takes account also of the lateral response to buffeting by
across-wind atmospheric turbulence components, using the methods of
ESDU 89049⁵. Comparisons of predictions with both model
and full-scale measurements and a discussion of methods of reducing
the response to vortex shedding are also included in ESDU
96030.

The calculation method is complex and it can realistically be
implemented only through a computer program. A program is currently
available as a Microsoft Excel* spreadsheet Module.

This Item gives guidance on the use of the Excel Module. Section
2 considers installation and running^† of the Module.
Section 3 describes the input data required and Section 4 the
output produced by the program. Section 5 describes a set of Worked
Examples. Appendix A provides some guidance on values for input
data.

The method can be applied for the following structure types and
flow conditions:

• parallel-sided, tapered and stepped structures,

• circular or regular polygon cross section (8 or more
sides),

• smooth or rough surfaces (for structures with ancillaries such
as ladders attached, the method applies only if the ancillary is
entirely within the main structure wake),

• cantilevered structures and structures between end
fixings,

• vertical, horizontal or inclined structures,

• structures with or without strakes,

• uniform or shear flow,

• smooth or turbulent flow,

• normal or yawed flow (a yawed wind affects the response only
if the structure is not vertical),

• natural wind (full scale), simulated wind (wind
tunnel),

• internal flows in which the structure causes a blockage of
less than 10%.

Example applications include stacks (chimneys) and process plant
towers, lighting standards and elements of lattice structures.

Several worked examples are described in Section 5 and some
guidance on sources of input data is given in Appendix A.

* Microsoft and Excel are trademarks of the Microsoft
Corporation

^† Some familiarity with the Microsoft Windows
operating system and the Microsoft Excel spreadsheet program is
assumed. For further guidance on these topics, consult the
appropriate Manuals or Help Files.

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