The efficiency of helical strakes for the suppression of vortex-excited oscillation of steel stacks

Helical strikes are well known as a device to suppress the vortex-excited oscillation of stacks and have been applied to some stacks to prevent the oscillation. Wind tunnel experiments on two-dimensional models were performed to reconsider the optimum configuration of the strakes. Based on the model experimental results, the effectiveness of the strakes was confirmed by experiments on an actual stack. Finally, the stack with strakes was shown to be more economical than the plain stack without strakes.