Wright-Patterson Air Force Base

About: Wright-Patterson Air Force Base is a other organization based out in Wright-Patterson AFB, Ohio, United States. It is known for research contribution in the topics: Laser & Mach number. The organization has 5817 authors who have published 9157 publications receiving 292559 citations. The organization is also known as: Wright-Patterson AFB & FFO.

Characterization of Organosilicon‐Infiltrated Porous Reaction‐Sintered Si3N4

Abstract: Polymeric organosilicon compounds such as hexaphenylcyclo-trisilazane and methylphenyl polysilane were used to infiltrate porous reaction-sintered silicon nitride. The in situ thermal decomposition of the infiltrated body under controlled atmosphere and temperature resulted in pronounced changes in the microstructure, increased densities, and significantly improved room-temperature strength. The silicon oxynitride phase present in some as-received materials is eliminated and the ratio of α- to β-phase silicon nitride increases during infiltration processing

Governing equations for weakly ionized plasma flowfields of aerospace vehicles

Abstract: A generalized set of conservative equations for simulating the flowfield in a hypersonic weakly ionized gas flows is presented. Additional numerical and physical complexities associated with the plasma state are identified and discussed, including the influence of external and space charge fields and the nonequilibrium coupling of reactive and nonreactive collisions. A restricted set of equations is then employed to simulate and analyze the flowfield of an air plasma generated by associative ionization. With use of a seven-species air model, details of the plasma flowfields are presented and compared with available experiments. Refined estimates of dissociation products, which are the precursors to the ionization reaction, are obtained. Specific attention is given to limiting forms of the electron diffusion coefficient and the influence of vibration-dissociation coupling. Details of the chemical reactions in the flowfield influencing the elastic and inelastic collisional energy transfer are reported to highlight the more important species and reaction mechanisms.

Fundamental studies of cavity-based flameholder concepts for supersonic combustors

Abstract: Experimentalandcomputationalinvestigationsofthee owe eldassociatedwithseveralcavity-basede ameholders in a nonreacting supersonic e ow are described. All cavity e ows were of the open type, that is, length-to-depth ratio L/D<10. Two values of L/D were studied with several offset ratios (OR) and aft ramp angles µ. Results indicate that the aft ramp angle plays an important role in determining the character of the shear layer that spans the cavity. For a rectangular cavity with OR=1 and µ=90 deg, a compression wave forms as the e ow separates from the cavity’ s upstream corner. A strong recompression occurs at the aft wall, and the e ow is visibly unsteady. The pressure on the cavity fore wall decreases steadily and the recompression process occurs more gradually with decreasing aftrampangle.Higherdrag coefe cientsandshorterresidencetimesarefoundin cavitieswithshallower ramp angles.

The flow over a wedge profile at mach number one

Abstract: : The flow over a wedge-shaped profile at zero angle of attack and with a free stream Mach number of one is computed using the hodograph method as simplified by the transonic law of similarity Drag coefficients are computed for several profiles (Author)