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Full-Text Articles in Engineering

Analysis Of An Electrospray Thruster With A Concave Propellant Meniscus, Adam Nicholas Huller Dec 2023

Analysis Of An Electrospray Thruster With A Concave Propellant Meniscus, Adam Nicholas Huller

Masters Theses

The low thrust, high specific impulse, and low mass of electrospray thrusters (ETs) make them ideal for maneuvering nanosatellites, especially with the new requirement to deorbit a satellite within five years of completing its mission. These innovative thrusters use electrohydrodynamic principles of electrospray (ES) to provide thrust. These principles have been subject to much research over the past decade, though much more research is needed to fully understand the underlying physics of these thrusters. The first part of this study establishes a procedure for analyzing the theoretical thrust performance of an ET, by using propellant properties and well-documented ES scaling …


Boundary Layer Measurements On The Bolt Ii Geometry Using Pressure And Temperature Sensitive Paints, Jacob Gaetano Butera Aug 2023

Boundary Layer Measurements On The Bolt Ii Geometry Using Pressure And Temperature Sensitive Paints, Jacob Gaetano Butera

Masters Theses

Hypersonic vehicles are subjected to an extreme aerothermodynamic environment dominated by intense thermal loading which is amplified further when the local boundary layer state transitions from a laminar to a turbulent state. Due to weight and complexity considerations, it is not feasible to incorporate thermal protection systems (TPS) over an entire hypersonic body. Therefore, it is critically important to identify and predict where the boundary layer will undergo transition such that the thermal protection system can be focused on the most at-risk areas. This work attempts to observe boundary layer transition on the Boundary Layer Transition (BOLT) II flight test …


Flow Control Over An Airfoil Using Synthetic Jet, Satyam Anil Mistry Aug 2023

Flow Control Over An Airfoil Using Synthetic Jet, Satyam Anil Mistry

Masters Theses

In this study, the unsteady, turbulent flow over NACA 0015 was analyzed using synthetic jets. The study focused on applying the numerical method using the commercial CFD solver Ansys Fluent. The synthetic jet simulation was carried out for Re = 896,000 for two angles of attack: 10 and 14 degrees. The optimal jet amplitude and jet frequency were determined from a range of amplitudes of 2.0 to 4.0 and frequencies of 0.4 Hz to 1.2 Hz while the jet location, jet angle, and jet width were fixed. The results showed that for both angles, the optimal amplitude and frequency were …


A Computational Analysis Of Hypersonic Store Separations, Ryan C. Savery Aug 2023

A Computational Analysis Of Hypersonic Store Separations, Ryan C. Savery

Masters Theses

Many current hypersonic vehicles involve shrouds, fairings, boosters, or ejectable payloads separating during flight. It is imperative that they do not strike each other after separation as this typically results in damage or loss of vehicle. This requires a detailed understanding of the flow features involved such as shock waves, expansion waves, shock reflections, and shock wave boundary layer interactions influencing the vehicles' attitude and trajectory. Experimental and flight tests of these scenarios are costly and need massive infrastructure which require difficult measurement techniques to characterize the flow field. Alternatively, numerical simulations can provide accurate, low-cost, and efficient predictions of …


An Experimental Investigation Of The Effect Of Narrowband Freestream Noise On Fundamental Transitional Shockwave-Boundary Layer Interaction Mechanisms, Zane Matthew Shoppell May 2023

An Experimental Investigation Of The Effect Of Narrowband Freestream Noise On Fundamental Transitional Shockwave-Boundary Layer Interaction Mechanisms, Zane Matthew Shoppell

Masters Theses

Recent work at the University of Tennessee Space Institute has demonstrated that the resonant behavior observed in the spectra of cylinder- and blunt-fin-generated XSBLIs is connected to fundamental fluid mechanisms within the boundary layer. Therefore, a test campaign was conducted to characterize the fundamental mechanisms that drive the low-frequency unsteadiness in cylinder- and blunt-fin-generated shockwave-boundary layer interactions, specifically shockwave-boundary layer interactions in which the incoming boundary layer is undergoing a laminar-to-turbulent transition. This research aims to develop a deeper understanding of such interactions and characterize the resonant behavior observed in past work by varying the sweepback angle of a hemicylindrical …


Enabling Premixed Hydrogen-Air Combustion For Aeroengines Via Laboratory Experiment Modeling, Christopher James Caulfield May 2023

Enabling Premixed Hydrogen-Air Combustion For Aeroengines Via Laboratory Experiment Modeling, Christopher James Caulfield

Masters Theses

All combustion systems from large scale power plants to the engines of cars to gas turbines in aircraft are looking for new fuel sources. Recently, clean energy for aviation has come into the foreground as an important issue due to the environment impacts of current combustion methods and fuels used. The aircraft industry is looking towards hydrogen as a new, powerful, and clean fuel of the future. However there are several engineering and scientific challenges to overcome before hydrogen can be deployed into the industry. These issues
range from storing the hydrogen in a viable cryogenic form for an aircraft …


Exploring The Structure And Dynamics Of Shock/Turbulent Boundary Layer Interactions Generated By Swept Compression Ramps In A Mach 2 Freestream, Daniel S. Allen May 2023

Exploring The Structure And Dynamics Of Shock/Turbulent Boundary Layer Interactions Generated By Swept Compression Ramps In A Mach 2 Freestream, Daniel S. Allen

Masters Theses

This thesis reports the investigation of the unsteadiness of a 2D and 3D swept shock-wave/turbulent boundary layer interaction (STBLI) and the effect the extent of subsonic flow has on the separation location. Two swept compression ramp cases are investigated at Mach 2 freestream conditions – a high sweep of 30 degrees and a low sweep of 10 degrees both having the same compression angle of 22.5 degrees in the vertical plane. Using a number of diagnostic techniques including stereoscopic and planar particle image velocimetry (PIV) and unsteady pressure sensitive paint (PSP) anchored with pressure transducers, the unsteadiness, the extent of …