Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 4 of 4
Full-Text Articles in Engineering
Wind Tunnel Testing For Drag Reduction Of An Aircraft Laser Turret, Christopher H. Snyder
Wind Tunnel Testing For Drag Reduction Of An Aircraft Laser Turret, Christopher H. Snyder
Theses and Dissertations
This study investigated the use of aft-mounted fairings and splitter plates to reduce the drag of a half-scale aircraft laser turret. Forces, moments, and pressure distributions were measured in the AFIT 1.5-m (5-ft) wind tunnel at Reynolds numbers between 3x10 to the 5th power and 9x10 to the 5th power based on the turret diameter. Oil traces indicated the nature of the flow near the surface of the unmodified turret and the surrounding area. Tufts placed on the turret, fairings, and splitter plates showed changes in separation regions when configurations were changed. The flow around the turret was characterized by …
Effect Of High Free Stream Turbulence On Film Cooling Using Double Row Of 30° Slant-Hole Injectors, Lilith I. Sorensen
Effect Of High Free Stream Turbulence On Film Cooling Using Double Row Of 30° Slant-Hole Injectors, Lilith I. Sorensen
Theses and Dissertations
In this study free stream turbulence levels from 7.3% to 17.8% are applied to film cooling over a flat plate with two rows of 30° slant holes using a wall jet as the main stream air supply and source of turbulence. Blowing ratios are varied from 0.25 to 2.0 and free stream velocities at injection range from 10 m/s to 85 m/s. A constant density ratio of 1.07 is kept throughout the experiment. Results show that for different magnitudes of blowing ratio free stream turbulence has a different influence on effectiveness. At the forward stations, where blow off was present …
Analysis Of Turbulence Models As Applied To Two- And Three-Dimensional Injection Flows, Clarence R. Chenault
Analysis Of Turbulence Models As Applied To Two- And Three-Dimensional Injection Flows, Clarence R. Chenault
Theses and Dissertations
A steady state solution of the full, three dimensional Favre averaged Navier Stokes equations, coupled with a second order Reynolds stress turbulence model (RSTM) and an eddy viscosity model were used to numerically simulate oblique injection into supersonic flow. Numerical results were compared to experimental data and the turbulence models were evaluated for accurate prediction of thermomechanical mean flow variables, Reynolds stresses, flowfield shock structure and boundary layer phenomena. The RSTM simulation resulted in physically consistent and accurate predictions for the mean flow and turbulent quantities. Simulations with the eddy viscosity model resulted in non-physical and inconsistent turbulence predictions. RSTM …
The Influence Of Surface Roughness On Supersonic High Reynolds Number Turbulent Boundary Layer Flow, Robert M. Latin
The Influence Of Surface Roughness On Supersonic High Reynolds Number Turbulent Boundary Layer Flow, Robert M. Latin
Theses and Dissertations
A comprehensive study of rough-wall high speed (M=2.9) high Reynolds number (Re/m = 1.9. 10 to the 7th power) turbulent boundary layer flow was performed consisting of experimental, analytical, and numerical methods. Six wall topologies consisting of a smooth and five rough surfaces (two and three dimensional machined roughness plates; and 80, 36, and 20 grit sand-grain roughened plates) were studied. A confocal laser scan microscope was used to measure the topography of the sand grain roughnesses. The experimental measurement techniques included a convention Pitot pressure probe, laser Doppler velocimetry, hot wire anemometry; color schlieren and laser sheet Mie scattering …