Measurements in the Boundary Layer on a Smooth Flat Plate in Supersonic Flow

Citation

Coles, Donald Earl (1953) Measurements in the Boundary Layer on a Smooth Flat Plate in Supersonic Flow. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/0DDW-9S38. https://resolver.caltech.edu/CaltechETD:etd-05092003-180051

Abstract

In Section I available measurements in low-speed turbulent boundary layer flow are compared with a simple analysis based on functional similarity, and the boundary layer is found to be unique within the accuracy of the experimental data. Some consequences of the mean equations of motion are obtained, including the distribution of shearing stress through the boundary layer, and an attempt is made to generalize the relationship known as the law of the wall to flows with variable density.

In Section II some problems encountered in the development and use of the floating surface element and other instrumentation are discussed in detail.

In Section III are presented measurements of mean and local surface friction carried out on a flat plate model in the 20-inch supersonic wind tunnel at the Jet Propulsion Laboratory. The boundary layer flow is studied for free stream Mach numbers of 2.0, 2.6, 3.7, and 4.5. The experiments, which involve nominal Reynolds numbers from 2 x 10⁵ to 9 x 10⁶, include a few measurements in laminar flow, but emphasize transition and the turbulent regime. The effectiveness of various tripping devices is mentioned, and the problem of defining an effective Reynolds number for the fully turbulent flow is discussed at length. Finally, turbulent boundary layer profile measurements are examined for consistency with low-speed data, with a generalized mixing length theory, and with the analysis of Section I of the present report.

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