Turbulence effects on some aerodynamic parameters of a circular cylinder at supercritical numbers

Aerodynamic parameters such as lift coefficient, Strouhal number and drag coefficient are required for estimating the response of structures due to wind action. These parameters for a circular cylinder are sensitive to a number of influences. Among these, effects of Reynolds number and turbulence are particularly prominent. Experimental data have been obtained from pressure and force measurements in a wind tunnel for different levels of turbulence intensity at critical and supercritical Reynolds numbers up to 10⁶. Blockage corrected results together with some full scale measurements have illustrated that some of these aerodynamics parameters become relatively insensitive to Reynolds number effects earlier in turbulent flow than in smooth flow. It is shown that modelling of full scale configurations with circular features can be performed satisfactorily provided the test Reynolds number in turbulent flow with turbulence intensity greater than 4%, is in excess of 2×10⁵; tests at Reynolds numbers below this value are shown to have little relevance to such full scale structures.