The present paper is aimed at providing a better understanding of the effect of interference and influence of strakes
for wind load on Thermal Power Station (TPS) chimneys. Measurements of across and along vibration have been
made on scale model of Panipat power station chimney, India. The aeroelastic model of the chimney has been tested
in a simulated atmospheric boundary layer of height 1.0 m in the Boundary Layer Wind Tunnel at IIT Roorkee, India.
The chimney model has been fabricated with FRP (fiber-reinforced plastic) at a geometric scale of 1:150 representing
a chimney with height of 100 m in prototype. The wind tunnel tests for the present study have been carried out with
the objective of obtaining the maximum along-wind and across-wind response of the chimney and this has been
expressed in terms of bending moments. In particular, the interference effect between other nearby structures of the
TPS has been investigated. Based on dimensional analysis measured values of chimney model have been converted
into prototype values.
In the present study, particular attention has been given to bending moment due to across-wind vibration, because it
has been found that across-wind vibration is more predominant for the case of interference at a 45o angle of wind
incidence. Bending moment due to across-wind vibration for interference is found to be approximately double
compared to that of stand-alone condition.
To control across wind vibration, strakes have been mounted over the top one-third height of the chimney. It is found
that there is a significant decrease in the magnitude of across as well as resultant bending moment in presence of
strakes.