TABLE OF CONTENTS 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 q gw or the radiation-adiabatic temperature T ra) 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 wall temperature. With these relations also fair estimations of the different properties can be made, if the boundary layer under consideration is weakly three-dimensional, and the stream-wise pressure gradient is not too large.
We consider exclusively the relevant thicknesses of laminar and turbulent flow boundary layers. Their dependencies on boundary-layer running length x, on the Reynolds number Re ref,x, and on the reference temperature T * are studied. Thermal and mass-concentration boundary layers can be treated likewise.
Boundary-Layer Thicknesses The flow boundary-layer was introduced in Sub-Section 4.3.1. We call it in the following simply "boundary layer". It causes a virtual thickening of a body (via its displacement properties), and it especially prevents a full re-compression of the external inviscid flow at the aft part of the body, where we have a flow-off separation of the boundary layer, and the formation of a wake. This is the cause of...
