Author(s): Walter H. Graf; Farid F. Mansour

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Abstract: Determination of drag coefficients from the conventional plots of drag coefficient, CD , versus Reynolds number, Re, is inadequate in the case of turbulent flow. Dimensional analysis has shown that the drag coefficient is a function of turbulence intensity, U 1, dimensionless turbulence scale, β/ D , and Reynolds number, Re. These parameters were combined in one term called the turbulence characteristics, , which was suggested by Ko and GRAF [3, 4]. The work presented herein is an attempt to determine the drag coefficient of sharpedged objects, such as cubes, and square rods. Based on the available data, two relationships were plotted between CD and (U′)2/CD respectively versus the turbulence characteristics, , for both the cube and the square rod. A relationship between(U′)2/CD versus turbulence characteristics was recommended for numerical determination of the drag coefficient in turbulent flow. In this relationship the curves developed for the cube and the square rod have the same trend as the curve of circular cylinder given by Ko and GRAF [3].

DOI: https://doi.org/10.1080/00221687509499710

Year: 1975