Wind induced oscillations of power station stacks. October 1962.

Abstract

Wind induced oscillations of welded steel smokestacks at Ptrmont have led to local buckling and fatigue cracks near the base. Observed double-amplitudes of the tops at 200 nfeet have been 2 to three feet. The most direct means of eliminating periodic interference or "buffeting' would be to prevent the regular shedding of eddies from upstream cylinders. The fitting of spoilers to the stacks of the kind investigated by Scruton and Walsh and by Weaver. The optimum would consist of four strakes with heights of 6% to 10% of the stack diameter woulnd helically around the stack with a pitch of twelve stack diameters. A single strake might suffice. An aesthetically acceptable solution might be to replace existing cat-ladders by a spiral set of steps incoroprating the spoilers.