Biomedical Engineering and Bioengineering Commons^™

Darcy-Weisbach Roughness Coefficients For Surfaces With Residue And Gravel Cover, John E. Gilley, Eugene R. Kottwitz

Biological Systems Engineering: Papers and Publications

Several types of hydraulic resistance factors may be present on upland agricultural areas. It is not known whether roughness contributions from individual elements are additive or if interactions between resistance factors may occur. In this study, Darcy-Weisbach roughness coefficients were measured on surfaces containing corn-soybeans, sorghum-cotton, and sunflower-wheat residue in addition to gravel cover. Varying rates of flow were introduced into a flume in which residue and gravel materials were securely attached. Roughness coefficients were calculated from measurements of discharge rate and flow velocity for Reynolds number values varying from approximately 1,200 to 13,000. The laboratory data were then used …