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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 217 records · Page 12

Turbulence measurements in a compressible boundary layer subjected to a shock-wave-induced adverse pressure gradient.

The rms intensities of fluctuating mass flux and total temperature and their correlation coefficients are given for the case of an adiabatic, Mach 4, axisymmetric shock-wave boundary-layer interaction. Data were obtained upstream, within, and downstream of the interaction by the use of constant temperature hot-wire anemometer. Turbulence spectra and quantitative behavior from oscilloscope traces are shown at selected locations. The measurements indicate that certain frequencies of the turbulence are increased as a result of the interaction and that the mass flux and total temperature fluctuations remain highly correlated over most of the boundary layer throughout the interaction. The present data are also transformed to rms intensities of fluctuating static temperature and velocity and compared with existing data obtained in adiabatic flows.

Rose, W. C.↗

Separated flows developing under increasingly adverse pressure gradients

Experimental results are presented for separating flows over a NASA GA(W)-1 airfoil with 2-percent trailing-edge thickness, with emphasis on the mean velocity data that demonstrate flowfield similarity downstream of separation. The length scale presently employed was selected because it furnishes the requisite matching point between the outer, mixing region flow and the back-flow.

Mehta, Jayesh M.↗

Bypass transition in boundary layers including curvature and favorable pressure gradient effects

Recent studies of 2-D boundary layers undergoing bypass transition were reviewed. Bypass transition is characterized by the sudden appearance of turbulent spots in boundary layer without first the regular, observable growth of disturbances predicted by linear stability theory. There are no standard criteria or parameters for defining bypass transition, but it is known to be the mode of transition when the flow is disturbed by perturbations of sufficient amplitude.

Volino, R. J.↗

Magnetic Compensation For Gravitational Pressure Gradient

In technique for partial simulation of low gravitation in diamagnetic or paramagnetic liquid, magnetic field having suitable gradient produces force counteracting gravitational force. Technique makes possible to perform low-gravity experiments on ground, at considerably less expense than in outer space.

Israelsson, Ulf E.↗