Across-wind response of tall circular chimneys to vortex shedding: Fid-Bau Portal

Across-wind response of tall circular chimneys to vortex shedding

Arunachalam, S. / Lakshmanan, N.

Abstract A semi-empirical method for predicting across-wind response of a circular chimney due to vortex shedding during lock-in region was earlier presented by the author. This involved use of only structural damping, with suitable modification of spectrum of modal lift force through a parameter ‘fact’, having a value of 0.45. When applied to three typical chimneys, the predicted across-wind base bending moment values showed good comparison with ACI code ACI-307-2008. In this paper, by considering additional experimental data from Wootton, a non-linear relation between the parameter ‘fact’ and the normalized rms tip deflection, $(\frac{σ_{y}}{D_{e}})$ is presented. The relationship is also verified using full-scale chimney data by Galemann and Ruscheweyh, Waldeck, and Melbourne. The suggested method is simple and useful for design offices and appears equally applicable both for steel and concrete chimneys.

Highlights • rms lift coefficient, C L,V approaches constant, and independent of Re number. • Enhanced response under lock-in, through non-dimensional parameter ‘fact’. • Closed form solution for normalized $(\frac{σ_{y}}{D_{e}})$ ; Base B.M. validated with ACI Code. • Non-linear relation for ‘fact’ with $(\frac{σ_{y}}{D_{e}})$ ; verified using full-scale data.