Measurement of extreme aerodynamic interference forces acting on circular cylinders in turbulent boundary layers

Extreme interference wind loads on circular cylinders are investigated in wind tunnel simulations of atmospheric boundary layers with high turbulence levels. Since for circular cylinders interference effects caused by vortex shedding are pronounced, the present work tries to clarify to which extent turbulence effects are reducing the interference in this case. Aerodynamic forces and moments were measured with a piezoelectric six-component wind tunnel balance. The balance is distinguished by a large dynamic range, low interferences and a high natural frequency. The numerous results include comparisons of mean values, r.m.s. values and extreme values of force coefficients with and without interference with reference to the velocity profiles and the turbulence levels in two different boundary layer simulations. Conclusions are drawn with regard to the application of the results in estimating wind loads on cylindrical structures.