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Aerodynamics and Fluid Mechanics

Air Force Institute of Technology

Compressibility

Publication Year

Articles 1 - 3 of 3

Full-Text Articles in Engineering

Development Of A Higher-Order Upwind Algorithm For Compressible Fluid Flow, Barry A. Croker Mar 2005

Development Of A Higher-Order Upwind Algorithm For Compressible Fluid Flow, Barry A. Croker

Theses and Dissertations

A global fourth-order solution method that incorporates compact differencing with Roe's approximate Riemann solver was investigated. This method was incorporated into a one-dimensional numerical simulation of the compressible Euler equations, and applied to a one-dimensional shock tube problem. The method was also extended to two dimensions, and applied to a two-dimensional shock tube problem and an advecting vortical structure problem on both rectilinear and curvilinear meshes. The results were compared to a third-order Roe scheme and a fourth-order compact difference scheme. An order of accuracy determination showed that it has an order of accuracy somewhere near fourth order, with absolute …


Experimental Investigation Of Compressible Boundary Layers Under The Influence Of Pressure Gradients, Raymond C. Wier Dec 1996

Experimental Investigation Of Compressible Boundary Layers Under The Influence Of Pressure Gradients, Raymond C. Wier

Theses and Dissertations

This study examined the effect of mild pressure gradients on the mean and turbulent flow of high-speed boundary layers. Three Mach numbers (1.7, 3.0 and 5.0) were investigated. Three pressure gradients were examined; a zero pressure gradient (ZPG), a favorable pressure gradient (FPG), and a combined pressure gradient (CPG). The CPG consisted of an adverse pressure gradient followed by a favorable pressure gradient. Conventional pressure probes, hot-wire and particle image velocimetry (PIV) were used to examine the flow. Measurement included mean velocity, velocity turbulence intensity, mass flux turbulence intensity and energy spectra. Instantaneous (10 nsec) Mie scattering flow visualizations were …


Compressible Turbulence Measurement In Low-Angle Injection Into A Supersonic Flow, Gregory J. Mccann Mar 1995

Compressible Turbulence Measurement In Low-Angle Injection Into A Supersonic Flow, Gregory J. Mccann

Theses and Dissertations

Mean flow and compressible turbulence measurements have been obtained at two stations downstream of low-angle supersonic injection into a Mach 3.0 flow (Re/m = 15 x 106). Data were collected using conventional Pitot and cone-static probes, single and multiple overheat cross-wire anemometry, and flow visualization techniques (shadowgraphs and schlierens). A direct measure of total Reynolds shear stress was accomplished using a turbulence transformation of the Reynolds-averaged Navier-Stokes equations. Results show compressibility effects, indicated by density fluctuations, to be large relative to the velocity fluctuations and on the same order in all three components. Compressibility appears to account for …