The report describes an experimental study of compressible turbulent boundary layers for which the upstream history was systematically varied. A series of experiments was conducted using both a supersonic half nozzle and a conventional flat plate for which the nozzle throat and flat plate leading edge can be temperature controlled. The supersonic nozzle provided a favorable upstream pressure gradient together with a controlled thermal history at the throat. The flat plate provided upstream temperature control with no pressure history. Velocity and temperature profile and heat-transfer measurements were made in a downstream region of zero-pressure-gradient and constant wall temperature. (Modified author abstract).

The report describes an experimental study of compressible turbulent boundary layers for which the upstream history was systematically varied. A series of experiments was conducted using both a supersonic half nozzle and a conventional flat plate for which the nozzle throat and flat plate leading edge can be temperature controlled. The supersonic nozzle provided a favorable upstream pressure gradient together with a controlled thermal history at the throat. The flat plate provided upstream temperature control with no pressure history. Velocity and temperature profile and heat-transfer measurements were made in a downstream region of zero-pressure-gradient and constant wall temperature. (Modified author abstract).

A comprehensive experimental and analytical study specifically designed to investigate upstream history and apparent stresses in incompressible, two-dimensional, turbulent boundary layers has been conducted. Hot-wire measurements of turbulent shear stress and longitudinal turbulence intensity, as well as velocity profiles and wall shear stress measurements, were made for six different pressure distributions. It was found that the turbulent shear stress is dependent upon the upstream history of the flow and not a unique function of the local velocity profile. A simple equation for the dissipation integral with a constant K was found to represent the data well. This expression was used with the mean-flow energy integral equation to obtain a practical method for predicting turbulent boundary layer behavior which accounts for upstream history. The predictions made with this method for the six pressure distributions of this study and for others extracted from the literature agreed well with the experimental data. (Author).

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