Accession Number : AD0859281

Title :   Propulsion System Flow Stability Program (Dynamic). Part III. Inlet Dynamic Distortion.

Descriptive Note : Final technical rept. 20 Jun 67-30 Sep 68 on Phase 1,

Corporate Author : NORTH AMERICAN ROCKWELL CORP LOS ANGELES CA LOS ANGELES DIV

Personal Author(s) : Martin, Arnold W. ; Kostin, Leonard C. ; Millstone, Sidney D.

Report Date : DEC 1968

Pagination or Media Count : 176

Abstract : Existing data from wind tunnel and flight tests were analyzed to obtain a better understanding of inlet-induced turbulence. Data were analyzed for both two-dimensional and axisymmetric external-internal shock compression inlets operating at mach numbers from 1.2 to 3.0, and from high to extremely low recoveries. As a secondary objective, the several statistical parameters used in the data analyses were evaluated. These included RMS amplitude, probability density, auto correlation, cross correlation, power spectral density, and cross power spectral density. For the configurations and conditions investigated, turbulence is primarily a function of boundary layer-shock interaction. Turbulence amplitude increases with increasing terminal shock strength, and decreases with distance downstream of the terminal shock. Turbulence consists of both random and nonrandom components, the latter tending to coincide with the acoustic frequencies of the inlet duct. As turbulence amplitude increases, there is a disproportionate part of the increase in the low frequency range. Turbulence energy tends to peak at the inlet acoustic frequencies. Power spectral density was found to be the most useful single statistical parameter. Least useful was the probability density which was found to be insensitive and difficult to interpret. (Author)

Descriptors :   (*TURBOJET ENGINES, JET BOMBERS), (*TURBOJET INLETS, TURBULENCE), DISTORTION, SUPERSONIC CHARACTERISTICS, STABILITY, WIND TUNNEL MODELS, MODEL TESTS, STATISTICAL ANALYSIS, POWER SPECTRA, BOUNDARY LAYER, SHOCK WAVES, INTERACTIONS, DUCT INLETS.

Subject Categories : Jet and Gas Turbine Engines

Distribution Statement : APPROVED FOR PUBLIC RELEASE