Basic Properties of Attached Viscous Flow

Basic concepts and results are discussed. Quantitative relations are given for the important properties of attached viscous flow, i. e., boundary-layer thick­nesses, wall shear stress, and the thermal state of the surface (either the heat flux in the gas at the wall qgw or the radiation-adiabatic temperature Tra) in two-dimensional flow. The relations for incompressible flow are extended by means of the reference-temperature concept to compressible perfect-gas flow. This suffices to show their basic dependencies on overall flow parameters and on the wall temperature. With these relations also fair estimations of the different properties can be made, if the boundary layer under consideration is two-dimensional or only weakly three-dimensional, and the stream-wise pressure gradient is not too large.