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- Fluid dynamics (2)
- Particle image velocimetry (2)
- Aerofoils (1)
- Air-to-surface missiles--Aerodynamics (1)
- Argon Ion Laser (1)
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- Beggar (Computer program) (1)
- Boundary layer (1)
- Buoyant convection (1)
- Computer fluid dynamics (1)
- Cone--Aerondynamics (1)
- Continuous Wave Laser (1)
- Drag (Aerodynamics)--Simulation methods (1)
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- Hypersonic flow (1)
- Hypersonic vehicles (1)
- Nonequilibrium flow (1)
- Particle size determination (1)
- Rarefied gas dynamics (1)
- Rayleigh Scattering (1)
- Stability--Mathematical models (1)
- Stalling (Aerodynamics) (1)
- Supersonic aerodynamics (1)
- Supersonic wind tunnel (1)
- Thermodynamics--Mathematical models (1)
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Articles 1 - 6 of 6
Full-Text Articles in Engineering
Dynamic Supersonic Base Store Ejection Simulation Using Beggar, Michael D. Johnson
Dynamic Supersonic Base Store Ejection Simulation Using Beggar, Michael D. Johnson
Theses and Dissertations
Static and dynamic conditions throughout various aft supersonic store separation events are examined using the Beggar Computational Fluid Dynamics (CFD) code from Air Force SEEK Eagle Office at Eglin Air Force Base, FL. An 8.9 deg half angle sphere cone is used for the carrier vehicle with an identically shaped store stowed within a hollow compartment in the aft section of the carrier body. Dynamic store separation simulations are implemented at a free-stream Mach of 2.9 with a Reynolds number of Re = 6.9 x 106/m referenced against carrier base diameter. Analysis covers multiple dynamic separation events along …
Filtered Rayleigh Scattering Measurements In A Buoyant Flow Field, Steven M. Meents
Filtered Rayleigh Scattering Measurements In A Buoyant Flow Field, Steven M. Meents
Theses and Dissertations
Filtered Rayleigh Scattering (FRS) is a non-intrusive, laser-based flow characterization technique that consists of a narrow linewidth laser, a molecular absorption filter, and a high resolution camera behind the filter to record images. Gases of different species have different molecular scattering cross-sections that become apparent as they pass through the interrogating laser light source, and this difference is used to discriminate between the different gaseous components. This study focuses on the behavior of a buoyant helium jet exiting horizontally into ambient air, and more specifically this jet’s tendency to form side lobes that are discharged from the core fluid under …
Characterization And Control Of Carbon Dioxide Seed Particle Image Velocimetry, Bartt G. Greene
Characterization And Control Of Carbon Dioxide Seed Particle Image Velocimetry, Bartt G. Greene
Theses and Dissertations
Particle Image Velocimetry (PIV) data was acquired in two separate supersonic wind tunnels with carbon dioxide (CO2) particles utilized as the seed material. Previous work in clean seeding showed CO2 could be used as seed material to produce velocity maps. This research provides the first quantitative assessment of particle response, particle size control via purge gas, and scalability using CO2 particles. A variety of feed tube and shroud configurations, in combination with varying volumetric flow rates of purge air were measured using a laser diffraction device. The CO2 particles were injected into the stilling chamber …
Determination Of Static And Dynamic Stability Derivatives Using Beggar, Michael E. Bartowitz
Determination Of Static And Dynamic Stability Derivatives Using Beggar, Michael E. Bartowitz
Theses and Dissertations
The static and dynamic pitch and roll stability derivatives of a finned, axisymmetric missile known as the Basic Finner were examined using a Computational Fluid Dynamics (CFD) approach. Stability derivatives are used to characterize vehicle motion, and knowledge of them is critical to the design of stable uncontrolled vehicles and control systems for controlled vehicles. Using CFD to characterize the motion of new munition designs has the potential to improve overall performance and reduce research and testing costs. The present analysis simulated forced oscillation and free oscillation of the Basic Finner model using the Air Force SEEK EAGLE Office's Beggar …
Piv-Based Examination Of Deep Stall On An Oscillating Air Foil, Daniel E. Fredberg
Piv-Based Examination Of Deep Stall On An Oscillating Air Foil, Daniel E. Fredberg
Theses and Dissertations
A number of studies suggest that the deep stall flow fields produced by a pure-pitch and a pure-plunge oscillating airfoil are equivalent, when effective angles of attack are matched. This assumption is examined using particle image velocimetry (PIV). Sinusoidal oscillations of a pure-plunge and pure-pitch airfoil with matched reduced frequency k = 3.93 and with kinematically equivalent amplitudes of effective angle of attack are comparatively examined using results of PIV in a free surface water tunnel at AFRL/RB, Wright Patterson AFB. Experiments were conducted at Re = 10,000 and Re = 40,000, based on free stream velocity and airfoil chord, …
Extending Cfd Modeling To Near-Continuum Flows Using Enhanced Thermophysical Modeling, Abram E. Claycomb
Extending Cfd Modeling To Near-Continuum Flows Using Enhanced Thermophysical Modeling, Abram E. Claycomb
Theses and Dissertations
The constitutive relations found in traditional Navier-Stokes-based computational fluid dynamics solvers are known to be limited in altitude. The presence of nonequilibrium phenomena beyond what these methods are able to predict becomes more prevalent at higher altitudes, or increasing Knudsen number. The bulk viscosity, normally assumed to be zero in most computational fluid dynamics applications, is examined as a means of increasing the range of applicability of computational fluid dynamics. The bulk viscosity model used was from recent calculations available in the literature, from a new anisotropic potential energy surface, and is restricted to temperatures below 2000 K. The normal …