ESDU 68020 presents data for the skin friction coefficients, shape parameter, momentum thickness, displacement thickness and boundary layer thickness for the turbulent boundary layer on a smooth flat plate with zero pressure gradient. It applies for Reynolds numbers based on streamwise distance of 100 000 to 1000 million for Mach numbers up to 5.0 and wall temperature/recovery temperature ratios in the range 0.25 to 2.00. An indication of the lowest values of Reynolds number for which the data are applicable is also given. The data for skin friction and momentum thickness are based on the semi-empirical method of Spalding and Chi. The data for shape parameter and boundary layer thickness are wholly empirical, based on a large quantity of test data. The applicability of the data is extended to two-dimensional supersonic flow over sharp wedges, the axisymmetric flow along cylinders and the axisymmetric supersonic flow about sharp-nosed cones by means of approximate factors applied to the flat plate data. The data given for compressible flow are for air or other gases having the ratio of specific heat capacities equal to 1.4 and a Prandtl number of 0.72. The data for incompressible flow are applicable to any fluid.

For the case of zero heat transfer, Appendix A provides accurate curve fits to the flat plate local and mean skin friction coefficients. Software for these calculations is provided as Toolbox CFM.