Turbulent Skin-Friction Coefficient and Momentum Thickness in Adverse Pressure Gradient

taken in drawing conclusions from the data of Linke, as drawn in Fig. 2, since it is calculated from experimentally obtained results for the total and pressure drag coefficients, and not by direct measurements of the skin-friction. Figure 3 is a typical plot of the data of Linke for total and pressure drag coefficients. As can be seen from this figure, calculation of the skin-friction drag is very arbitrary because of the scatter in the data.