Discussion: “An Experimental Evaluation of Drag Coefficient for Rectangular Cylinders Exposed to Grid Turbulence” (Courchesne, J., and Laneville, A., 1982, ASME J. Fluids Eng., 104, pp. 523–527)

Abstract

ConclusionThe purpose of the present investigation was to systematically define the effect of turbulence on the drag. The results offer a semi-consistent behavior. Cylinders with HID > 0.5 follow a regular influence with turbulence, that is, an increased in the level of turbulence seems to move the smooth flow C DC of a given HID section to the C DC of an equivalent increased HID section. Cylinders with HID < 0.5 do not reach the maximum C DC of 2.9 as the level of turbulence is increased. It also suggests that the vortices strength as well as their formation and the afterbody length HID remain predominant variables in turbulent flow with the additional turbulence intensity. The complex equilibrium in the near wake is a concept that has to be more investigated and how perturbations, as turbulence contained in main stream, play a role in this equilibrium remains to be investigated more fully.