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Title: COMPUTATION OF THIN AIRFOIL AERODYNAMICS FOR MICRO AIR VEHICLE APPLICATIONS
Creator: Baez Guada, Alejandro
Date: 2013-04-29, 2013-05
Description: With the significant interest in the development of micro air vehicles with gust resistant capabilities, active flow control has become a main...
Show moreWith the significant interest in the development of micro air vehicles with gust resistant capabilities, active flow control has become a main challenge in enhancing flight conditions. The current flow control techniques are limited at suppressing fluctuations in the lift induced by unsteady freestreams and while undergoing fast maneuvers. As a result of the time delay associated with the actuation input and formation of the leading edge vortex, closed-loop controllers are limited by the bandwidth to suppress fluctuation in the lift under unsteady freestreams. Therefore, the recognition of the direct interaction of the controller with the formation of vortex shedding suggests the development of new techniques for flow control. For the sinusoidal oscillating freestream, the knowledge of the time scales in response to actuation and the phase between the unsteady freestream and lift time series are useful in the implementation of the feed forward controllers suppressing lift fluctuations. Moreover, prospective solutions have been conceptualized in the implementation of the leading edge separation sensor and the gust load alleviation controller that would allow the instantaneous response to enhance lift under unsteady freestreams conditions. With the increasing computational power and reliance on turbulence models, the numerical simulations facilitate the investigation of thin airfoil aerodynamics at post-stall angles of attack under steady and unsteady freestreams. The computations of turbulent flows for external flow aerodynamics are challenging as a result of the presence of separated flow. The detachment of boundary layers is by nature three-dimensional and time dependent. Therefore, simulating these flows is problematic and requires high computational cost. Thin shear layers are common in external aerodynamic flows demanding very fine near-wall discretization to solve for separation points. The growth of the boundary layer, separation, and mixing length scales require complex approaches for accurate results. xviii In the present study, the performance of the turbulence models is investigated in numerical predictions of thin airfoil aerodynamics at post-stall angles of attack. The results suggest that low computational cost turbulence models fail at treating separated flows. Moreover, the instantaneous locations of separation and stagnation points in response to the changes in the lift for steady and unsteady flows were investigated. The amplitude and frequency of the time series of the separation and stagnation point location are highly correlated with the characteristics of the lift oscillations. Therefore, the recognition of separation or stagnation point locations at the leading edge of the wing could provide the direct information of the gains and drops in the lift for active flow control applications.
M.S. in Aerospace and Mechanical Engineering, May 2013
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Title: RECRYSTALLIZATION MECHANISM FOR TWO NICKEL BASED SUPERALLOYS
Creator: Balandra, Ombeline
Date: 2016, 2016-05
Description: The demand for enhanced structural performances materials is growing every year. A lot of technological advancements in the sector of...
Show moreThe demand for enhanced structural performances materials is growing every year. A lot of technological advancements in the sector of aerospace or nuclear are in constant need for materials with good mechanical properties and high temperature resistance. The alloys commonly used for these features are Nickel-based superalloys as they exhibit high strength and good resistance to corrosion and oxidation. To improve their mechanical behavior, recent studies have focused on grain refinement methods. Among these methods to obtain the finest grain size distribution, one is particularly advantageous for it low cost and feasibility: severe plastic deformation.In this study, the deformation mechanism of two high performance, low stacking fault energy nickel-based alloys are investigated. The first alloy, Monel 400, it is a single FCC phase material. The second one is Inconel 625 wich has a two-phase (γ and γ’) microstructure. During hot deformation, the γ’ precipitate may be present in the γ phase and above a certain solvus temperature, the γ phase exists in the material. The restoration mechanism for FCC crystals is well known, and particular attention was given in this report to the recrystallization response and flow behavior of Inconel 625 for sub-solvus temperatures. In the introduction a brief review of the current state of literature on the deformation response of Nickel-based superalloys is provided. Samples were compressed under various temperatures and strain rate conditions using a Gleeble-3500 thermo-mechanical simulator and flow stress curves were extracted. To characterize both qualitatively and quantitatively the deformation, samples were then analyzed using standard microscopy, scanning electron microscopy and electron backscatter diffraction analysis. The resulting images and maps combined with flow stress curves have lead to the formulation of constitutive models of the recrystallization process using three parameters, the stress, grain size and recrystallized volume fraction.The data shows that deformation is first accommodated through dynamic recovery with the formation of sub-grains structures. Then, after the experimental strain reaches a critical value, recrystallized grains form within the microstructure. EBSD analysis show a trend for new recrystallized grain to grow under certain conditions. Results show a trend of increasing the grain size with increasing the strain and decreasing the Zener-Hollomon parameter and an increasing recrystallized volume fraction with increasing the strain and Zener-Hollomon parameter.
M.S. in Material, Mechanical and Aerospace Engineering, May 2016
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Title: Calibration of the pitot steammeter
Creator: Carr, A. L, Strube, H. L
Date: 2009, 1906
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/calibrationofpit00carr
Thesis (B.S.)--Armour Institute of Technology, 1906 B.S. in Mechanical Engineering, 1906

Title: Calibration of the pitot tube
Creator: Dreffein, Henry A., Mcburney, Edward, Jr
Date: 2009, 1905
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/calibrationofpit00dref
Thesis (B.S.)--Armour Institute of Technology, 1905 B.S. in Mechanical Engineering, 1905

Title: Calibration test of electric water meter
Creator: Steward, W. H., Jr
Date: 2009, 1915
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/calibrationtesto00stew
Thesis (B.S.)--Armour Institute of Technology, 1915 Bibliography: leaves 19-27 B.S. in...
Show morehttp://www.archive.org/details/calibrationtesto00stew
Thesis (B.S.)--Armour Institute of Technology, 1915 Bibliography: leaves 19-27 B.S. in Mechanical Engineering, 1915
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Title: VALIDATION AND CHARACTERIZATION OF TURBULENCE IN AN AORTIC COARCTATION
Creator: Arzani, Amirhossein
Date: 2012-04-25, 2012-05
Description: Image based, patient speci c computational uid dynamics (CFD) modeling has gained dramatic attention in evaluation of health and disease...
Show moreImage based, patient speci c computational uid dynamics (CFD) modeling has gained dramatic attention in evaluation of health and disease progression. With the popularity of these techniques in clinical settings the need to address how these numerical predictions validate against the empirical data becomes more imperative. Validation studies have primarily been used in vitro models, since experiments are dif- cult to control in vivo, and in vivo conditions are challenging to replicate numerically. However, in vivo validations are essential for a more reliable assessment. Moreover, direct quanti cation of turbulence, necessary for diagnostic purposes, makes the validation process more challenging in turbulent ows. A phase-contrast magnetic resonance imaging (PCMRI) method was used to obtain turbulent kinetic energy (TKE) in an aortic coarctation, a congenital disease, where the aorta narrows blocking the passage of blood to a great portion of the body. A 3D patient-speci c computer model of the aortic coarctation was constructed from the MRI data. Direct numerical simulation was performed to solve the Navier-Stokes equations using a stabilized nite element method. Based on the PCMRI procedures, di erent methods were used to compute TKE from the CFD velocity data, and were compared to the PCMRI data. The velocity data obtained from CFD was also used to study the ow topology by computing the Finite-Time Lyapunov Exponent (FTLE) eld, and the Lagrangian coherent structures (LCS). The TKE results showed relative good agreement between the in vivo measurements and the CFD predictions of TKE. Observed di erences were within expectations due to modeling, measurement and numerical errors.
M.S. in Mechanical, Materials, and Aerospace Engineering, May 2012
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Title: THE DEVELOPMENT OF A CRYOGENIC OVER-PRESSURE PUMP
Creator: Alvarez, Matthew L.
Date: 2001-07-17, 2012-07
Description: The Dark Energy Survey (DES) project will study the accelerated expansion of the universe. In order to further study this phenomenon,...
Show moreThe Dark Energy Survey (DES) project will study the accelerated expansion of the universe. In order to further study this phenomenon, scientists have devised a method of creating an array of charged couple devices (CCD) to capture images that will be studied. These CCDs must be cooled and remain at 173K to eliminate thermal gradients and dark current. Therefore, a two-phase CCD liquid nitrogen (LN2) cooling system was designed to maintain the array of CCDs at a constant temperature. However, the centrifugal pump used to supply LN2 has a mean time between failure (MTBF) of approximately two thousand-eight hundred hours (116 days). Because of the low MTBF of the centrifugal pump, a new pump is being considered to replace the existing one. This positive displacement pump is a simpler design that is expected to have a MTBF that will exceed 116 days (2800hrs). This positive displacement reciprocating pump, also known as, the cryogenic over-pressure pump (OPP), was tested in February 2012 and successfully cooled the CCD array to 173K. Though un t for service for DES CCD cooling system, the overall concept of this pump has been proven. Typical ow rates, pressures, and temperatures trends have been captured via instrumentation and are speci c to the operation of future over-pressure pumps.
M.S. in Mechanical and Aerospace Engineering, July 2012
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Title: Analysis and design of a power plant for a proposed department store and office building
Creator: Ratcliff, W. A.
Date: 2009, 1905
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/analysisdesignof00ratc
Thesis (B.S.)--Armour Institute of Technology

Title: AN ELECTRICITY-ASSISTED FRICTION STIR WELDING PROCESS WITH CURRENT APPLIED FROM THE WORKPIECE SIDE SURFACES
Creator: Eamkulworapong, Sakda
Date: 2011-11-09, 2011-12
Description: Friction stir welding (FSW) has many promising industrial applications due to its solid-state nature and the associated benefits. However,...
Show moreFriction stir welding (FSW) has many promising industrial applications due to its solid-state nature and the associated benefits. However, some challenges still exist, such as: (i) a high tool loading force is required to generate the friction heat needed to soften the material, which often limits tool life, and (ii) FSW often desires a narrow temperature range near but below the melting point, which makes it challenging to get a deep welding depth without melting the top surface. Electricity-assisted FSW (EAFSW) has been previously studied in literature, where the current is applied from the tool. The electricity generates additional resistance heat, which may increase the welding efficiency and decrease the required tool loading force. However, this approach yields a relatively high temperature gradient in the depth direction, and is difficult to effectively enhance the welding depth without melting the top surface. In this thesis, a new EAFSW process is proposed and studied, where the current is applied from the workpiece side surfaces. The study is based on an experimentally tested physics-based model, and it shows that the new EAFSW process has a great potential to enhance the welding efficiency, decrease the required tool loading force, and increase the welding depth without melting the top surface.
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Title: Installation and test of an International Harvester co. gasoline engine
Creator: Peck, Winfield, Llewellyn, Kenneth
Date: 2009, 1911
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/installationtest00peck
Thesis (B.S.)--Armour Institute of Technology, 1911 B.S. in Mechanical Engineering, 1911

Title: Analysis of Murgue's Theory for Centrifugal Blowers and Pumps
Creator: Spitzglass, Jacob M.
Date: 2009, 1913
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/analysisofmurgue00spit
Thesis (B.S.)--Armour Institute of Technology

Title: SHIP STATE AND COVARIANCE PROPAGATION USING TIME SERIES ANALYSIS AND FORECASTING
Creator: Katre, Aniruddha
Date: 2014, 2014-05
Description: The Navy's Unmanned Combat Aerial System (N-UCAS) program is currently developing technology for autonomous shipboard landing of unmanned...
Show moreThe Navy's Unmanned Combat Aerial System (N-UCAS) program is currently developing technology for autonomous shipboard landing of unmanned aerial vehicles (UAVs). A high accuracy and high integrity relative navigation algorithm using carrier phase di erential GPS measurements and high rate inertial sensor data has been implemented to land the UAV. Such an algorithm requires ship state information to be broadcast to the aircraft via a VHF data link. The data link is susceptible to failure for reasons such as interference from jamming. This thesis considers the problem of precise ship state propagation on board an aircraft during a data link outage occuring when it is too late for the aircraft to abort its landing approach. Accurately quantifying the estimate error covariance is important for a high integrity and accuracy navigation algorithm. Therefore this thesis focuses on algorithms that can propagate the ship state as well as determine the propagation error covariance. Initially, a simple state propagation using kinematic equations for linear motion is tested. Seakeeping and Maneuvering theories used to model the dynamics of a sea vessel are also considered. However, analysis shows that due to constraints imposed by a data link outage and complexity in accurately modeling some parameters in the ship dynamic model, these two approaches are infeasible. As an alternative to kinematic and dynamic modeling, Time Series Analysis and Forecasting methods for ship state propagation are investigated. This work introduces parametric modeling and forecasting of a time series using linear stochastic models. Maximum likelihood estimate (MLE) and outer product of gradients (OPG) algorithms are implemented for faithful parameterization of time series using ARIMA models. Expressions for forecasting and forecast error variance quanti cation are also developed. These algorithms are then tested using ship data provided by the N-UCAS program.
M.S. in Mechanical and Aerospace Engineering, May 2014
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Title: Closed nozzle tests of a forty gallon chemical extinguisher
Creator: Corman, A., Cowles, R. D., Owen, W. R., Tronvig, W. P.
Date: 2009, 1917
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/closednozzletest00corm
Thesis (B.S.)--Armour Institute of Technology

Title: The coefficient of friction of ball bearings and horse power to drive
Creator: Rehfeldt, H. F.
Date: 2009, 1919
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/coefficientoffri00rehf
Thesis (B.S.)--Armour Institute of Technology

Title: A commericial test of 350 hp Stirling boiler
Creator: Furry, William S, Matchett, James C.
Date: 2009, 1907
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/commericialtesto00furr
Thesis (B.S.)--Armour Institute of Technology

Title: Coke breeze briquetting
Creator: Belke, W. E.
Date: 2009, 1918
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/cokebreezebrique00belk
Thesis (B.S.)--Armour Institute of Technology; Biblography: leaf 83

Title: Comparative test of centrifugal pressure blowers
Creator: Conlin, W. F., Holmes, W. E.
Date: 2009, 1909
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/comparativetesto00conl
Thesis (B.S.)--Armour Institute of Technology; Includes index

Title: Comparative test of centrifugal blowers
Creator: Griffiths, Francis H, Cummins, G. Fred
Date: 2009, 1911
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/comparativetesto00grif
Thesis (B.S.)--Armour Institute of Technology, 1911 B.S. in Mechanical Engineering, 1911

Title: Comparative tests on small steam pumps
Creator: Lewis, R. L., Monahan, J. E.
Date: 2009, 1908
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/comparativetests00lewi
Thesis (B.S.)--Armour Institute of Technology

Title: Comparative tests of small laminated and solid spruce beams for aeroplane construction
Creator: James, Sydney V
Date: 2009, 1911
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/comparativetests00jame
Thesis (B.S.)--Armour Institute of Technology; Bibliography: leaf 19

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