Direct Numerical Simulation Of Pressure Fluctuations Induced By Supersonic Turbulent Boundary Layers,
2018
Missouri University of Science and Technology
Direct Numerical Simulation Of Pressure Fluctuations Induced By Supersonic Turbulent Boundary Layers, Chao Zhang
Doctoral Dissertations
"Direct Numerical Simulations are used to generate a database of high-speed zero-pressure-gradient turbulent boundary layers developing spatially over a flat plate with nominal freestream Mach number ranging from 2:5 to 14 and wall-to-recovery temperature ranging from 0:18 to 1:0. The flow conditions of the DNS are representative of the operational conditions of the Purdue Mach 6 quiet tunnel, the Sandia Hypersonic Wind Tunnel at Mach 8, and the AEDC Hypervelocity Tunnel No. 9 at Mach 14. The DNS database is used to gauge the performance of compressibility transformations, including the classical Morkovin's scaling and strong Reynolds analogy as well as …
The Separation Of Shear-Driven Liquid Films From A Sharp Corner,
2018
Missouri University of Science and Technology
The Separation Of Shear-Driven Liquid Films From A Sharp Corner, Zahra Sadeghizadeh
Doctoral Dissertations
"The separation of shear-driven liquid films occurs in many engineering applications such as port fuel injected engines, demisters, and gas transfer lines. Despite the importance of this problem, the details of the interaction between operating parameters such as liquid flow rate, gas velocities and liquid film properties on the forces at the expanding corner are still not clear. To enhance the insight on the complicated interaction between the gas and liquid phases, the shear-driven liquid flow around a corner has been studied both experimentally and analytically in this work. The effect of the complex liquid film structure on liquid mass …
Gust Alleviation System For General Aviation Aircraft,
2018
Old Dominion University
Gust Alleviation System For General Aviation Aircraft, Lucas Coleman Mills
Mechanical & Aerospace Engineering Theses & Dissertations
A designed control motion scheme to improve passenger comfort in general aviation aircraft by reducing normal acceleration and pitch rate due to turbulence is investigated. An aerodynamic math model is created for ViGYAN’s Active Ride Improvement System flight article, a one-eighth scale Pilatus Porter PC-6 with conventional forward main wing, aft horizontal and vertical tails, and a single engine with tractor configuration. The test article incorporates a full-span gust flap and forward mounted gust sensor to mechanize the gust alleviation control system, and these features are present in the dynamic model. The model is a two degree of freedom linear …
Development Of A Cfd Model Of The Catalytic Combustion Of A Microtube Multi-Mode Propulsion System,
2018
Missouri University of Science and Technology
Development Of A Cfd Model Of The Catalytic Combustion Of A Microtube Multi-Mode Propulsion System, Andrew Paul Taylor
Masters Theses
"This thesis presents the process and results of the development of a computational fluid dynamics (CFD) model in ANSYS Fluent 18.1 on the catalytic decomposition of a novel liquid monopropellant in a microtube in order to gain deeper insights than what is available through the experimental data. The CFD model was created using the Euler- Euler Multiphase model in conjunction with the Heterogeneous Reaction submodel. Such a choice of modeling setting was backed up by theory and benchmark computations on multiphase and compressible flow, shown in Section 3 and Appendix A. It was found that the previously determined one-step reaction …
The Design Of A Rocket Propulsion Labview Data Acquisition And Control System,
2018
University of Texas at El Paso
The Design Of A Rocket Propulsion Labview Data Acquisition And Control System, Dylan Allan Ott
Open Access Theses & Dissertations
When designing a rocket engine, both the propulsion system and propellant choice(s) are an important deciding factor. Desired rocket engine behavior, specific impulse, and levels of thrust are all different between the various propulsion systems. A bi-propellant cryogenic liquid 5lbf, 500lbf, and 2000lbf rocket engine was designed and manufactured by UTEP. The 5lbf rocket engine is a Reaction Control Engine and the 500lbf and 2000lbf rocket engine is a throttleable Main Engine. To provide a reliable and safe data acquisition and control system for this experiment, a Real-Time control platform was needed. A compact DAQ system was purchased and configured …
Relationship Between Airline Category, Geographical Region, And Safety Performance,
2018
Walden University
Relationship Between Airline Category, Geographical Region, And Safety Performance, Peter Simpson
Walden Dissertations and Doctoral Studies
Passengers rank safety as a key factor in airline choice. Thus, safety performance impacts an airline's ability to attract customers. The purpose of this correlational study was to examine the relationship and difference between airline category low-cost carriers (LCCs) and full-service carriers (FSCs), geographical region, and safety performance measured by accident rates. The target population comprised all airlines in all countries that had an accident during the 14-year period 2004 to 2017. Data consisted of archival data of all global airline accidents and airline departure frequencies for the 14-year period. The theory of organizational accidents in complex sociotechnical systems explains …
Investigation Of 2195 And 2219 Post Weld Heat Treatments For Additive Friction Stir Lap Welds,
2017
University of New Orleans
Investigation Of 2195 And 2219 Post Weld Heat Treatments For Additive Friction Stir Lap Welds, Matthew Champagne
LSU New Orleans Theses and Dissertations
To evaluate potential uses for friction stir welding in additive manufacturing, two separate parts were fabricated, one of 2195-T84 and the other 2219-T87, utilizing fixed pin techniques and additive lap welds. The parts were cut into samples, artificially aged and subjected to Rockwell hardness (HRB), Vickers hardness, micrographic photography, and metallographic imaging on both pre- and post- heat treatment. Additionally, tensile testing was performed on the heat-treated samples. A comparisons of test results showed a minimal increase in the yield strength of the 2195-T84 samples compared to as-welded tensile results obtained from a previous project. The ultimate tensile strength was …
Design, Manufacture, And Structural Dynamic Analysis Of A Biomimetic Insect-Sized Wing For Micro Air Vehicles,
2017
University of New Orleans
Design, Manufacture, And Structural Dynamic Analysis Of A Biomimetic Insect-Sized Wing For Micro Air Vehicles, Jose Enrique Rubio
LSU New Orleans Theses and Dissertations
The exceptional flying characteristics of airborne insects motivates the design of biomimetic wing structures that can exhibit a similar structural dynamic behavior. For this purpose, this investigation describes a method for both manufacturing a biomimetic insect-sized wing using the photolithography technique and analyzing its structural dynamic response. The geometry of a crane fly forewing (family Tipulidae) is acquired using a micro-computed tomography scanner. A computer-aided design model is generated from the measurements of the reconstructed scanned model of the insect wing to design the photomasks of the membrane and the venation network required for the photolithography procedure. A composite …
Synthetic Jet Actuator-Based Aircraft Tracking Using A Continuous Robust Nonlinear Control Strategy,
2017
Embry-Riddle Aeronautical University
Synthetic Jet Actuator-Based Aircraft Tracking Using A Continuous Robust Nonlinear Control Strategy, N. Ramos-Pedroza, W. Mackunis, M. Reyhanoglu
Publications
A robust nonlinear control law that achieves trajectory tracking control for unmanned aerial vehicles (UAVs) equipped with synthetic jet actuators (SJAs) is presented in this paper. A key challenge in the control design is that the dynamic characteristics of SJAs are nonlinear and contain parametric uncertainty. The challenge resulting from the uncertain SJA actuator parameters is mitigated via innovative algebraic manipulation in the tracking error system derivation along with a robust nonlinear control law employing constant SJA parameter estimates. A key contribution of the paper is a rigorous analysis of the range of SJA actuator parameter uncertainty within which asymptotic …
Outer Space: A Steam Voyage,
2017
SciArt Exchange
Outer Space: A Steam Voyage, Jancy Mcphee
The Transdisciplinary STEAM+ Journal
SciArt Exchange offers multi-disciplinary art contests, artwork events, consulting, training and community resources to support science and technology education, collaboration, and innovation. Using a science-integrated- with-art approach, SciArt Exchange supports, prepares, and convenes people of all ages, backgrounds and affiliations to discuss and potentially solve space, science, and technology challenges. This field note shares the Humans in Space Art Program and the Project Mars Competition.
The Effect Of Z-Binding Yarns On The Electrical Properties Of 3d Woven Composites,
2017
Missouri University of Science and Technlogy
The Effect Of Z-Binding Yarns On The Electrical Properties Of 3d Woven Composites, Mohamed Nasr Saleh, Arief Yudhanto, Gilles Lubineau, Constantinos Soutis
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Electrical resistance monitoring (ERM) has been used to study the effect of the z-binding yarns on the initial electrical resistance (ER) and its change of three architectures of 3D woven carbon fiber composites namely (orthogonal "ORT", layer-to-layer "LTL" and angle interlock "AI") when tested in tension. Specimens are loaded in on-axis "warp" and off-axis "45°" directions. In situ ERM is achieved using the four-probe technique. Monotonic and cyclic "load/unload" tests are performed to investigate the effect of piezo-resistivity and residual plasticity on resistance variation. The resistance increases for the off-axis loaded specimens (∼90%) is found to be higher than that …
A Comparison Of The Aerodynamic Centers For Panel Code Compressible Corrections And Openfoam 5 For Mach 0.1 To 0.8,
2017
Utah State University
A Comparison Of The Aerodynamic Centers For Panel Code Compressible Corrections And Openfoam 5 For Mach 0.1 To 0.8, Dustin Weaver
All Graduate Plan B and other Reports, Spring 1920 to Spring 2023
It is known that the aerodynamic center changes from quarter chord to half chord from incompressible to compressible flows on airfoils. Compressible corrections are derived and implemented in a vortex panel code. These results will be used to find the aerodynamic centers for the specified Mach range of 0.1 to 0.8 in 0.1 increments within - 6 to 6 degrees angle of attack. OpenFOAM 5 cases will be created with specific meshes and settings. The results calculated from OpenFOAM 5 will be compared to the results obtained from the compressible corrections.
Multiphase Flow Modeling For Design And Optimization Of A Novel Down-Flow Bubble Column,
2017
Louisiana State University and Agricultural and Mechanical College
Multiphase Flow Modeling For Design And Optimization Of A Novel Down-Flow Bubble Column, Mutharasu Lalitha Chockalingam
LSU Doctoral Dissertations
The application of the Euler-Euler framework based Computational Fluid Dynamics (CFD) models for simulating the two-phase gas-liquid bubbly flow in down-flow bubble columns is discussed in detail. Emphasis is given towards the modelling and design optimization of a novel down-flow bubble column. The design features of this novel down-flow bubble column and its advantages over a conventional Plunging Jet down-flow bubble column are discussed briefly. Then, some of the present challenges in simulating a conventional Plunging Jet down-flow bubble column in the Euler-Euler framework is highlighted, and a sigmoid function based drag modification function is implemented to overcome those challenges. …
Flight Dynamics: Flying Qualities Of Handling Factors Are Engineered Into The Aircraft Design,
2017
Minnesota State University, Mankato
Flight Dynamics: Flying Qualities Of Handling Factors Are Engineered Into The Aircraft Design, Nihad E. Daidzic
Aviation Department Publications
Flight dynamics is an aerospace engineering discupline that addresses aircraft stability and controllability. It is also mathematically very intensive and is traditionally the most difficult in the pilot training curriculum. Ultimately, it does not matter how good steady-state performance of an aircraft design is if its flying (handling) qualities are deficient. Paradoxically, the first airplane Wright Flyer, was statically and dynamically unstable, had large control authority, and was difficult to fly. We've come a long way since those early days, but stability is still vitally important in aircraft design and flight ops. The focus of this article will be airplane …
Rotordynamic Enhancement By Utilizing The Controlled Hydrostatic Injection Of Hybrid Air Foil Bearing,
2017
University of Texas at Arlington
Rotordynamic Enhancement By Utilizing The Controlled Hydrostatic Injection Of Hybrid Air Foil Bearing, Behzad Zamanian Yazdi
Mechanical and Aerospace Engineering Dissertations - Archive
Air foil bearings (AFBs) are introduced as promising bearings for oil-free turbomachinery applications. Air foil bearing (AFB) technology has made substantial advancement during the past decades and found its applications in various small turbomachinery. AFBs provide reliable operation at high speed and high temperature with negligible power loss. However, rotordynamic instability, friction and drag during the start/stop, and thermal management are still challenges for further application of the technology. Hybrid Air Foil Bearing (HAFB) technology utilizes the radial injection of externally pressurized air into the traditional hydrodynamic AFB’s film thickness through orifices attached to the top foil. HAFB is one …
Optimization Of Aircraft Tow Steered Composite Wing Structures,
2017
University of Texas at Arlington
Optimization Of Aircraft Tow Steered Composite Wing Structures, Micheal Chamberlain Henson
Mechanical and Aerospace Engineering Dissertations - Archive
An efficient methodology for design of aircraft composite wing structures is presented. The developed approach provides a flexible and integrated strategy to leverage advantages of composite material tow steering to achieve more effective wing designs. This is accomplished by including the coupling between OML geometry, aerodynamics and structural response. Structural and aerodynamic analyses are derived from parametric aircraft geometry and assembled into a framework for aero-structural wing sizing. A Ritz equivalent plate solution is extended to model composite materials with variable fiber path geometry. The structural modeling approach is implemented to automate creation of both Ritz and finite element analyses. …
A Micromechnics Approach To Predicting The Onset Yielding Envelope Of Particulate Composite Materials,
2017
University of Texas at Arlington
A Micromechnics Approach To Predicting The Onset Yielding Envelope Of Particulate Composite Materials, Behrooz Karimi
Mechanical and Aerospace Engineering Dissertations - Archive
Composite materials fail for various reasons and extensive research has been conducted both experimentally and theoretically. However, theoretical prediction of composite failure by yielding seems scarce. Adding reinforcing elements to matrix significantly affects the structural behavior of composite materials. The inserted particles on one hand obstruct the progress of cracks and on the other hand cause stress concentration on the interface of the particle-matrix and eventually influence the ultimate strength of the material. In this research, we study the interface stresses and strength in particulate reinforced composites under uniform mechanical and thermal loading. We theoretically obtain failure envelopes for particulate …
Towards The Fabrication Of Bioresorbable Constructs With Customized Properties Using Additive Manufacturing,
2017
University of Texas at Arlington
Towards The Fabrication Of Bioresorbable Constructs With Customized Properties Using Additive Manufacturing, Prashanth Ravi
Mechanical and Aerospace Engineering Dissertations - Archive
Additive Manufacturing (AM) has been employed to fabricate medical constructs for over two decades. This dissertation investigates the effects of AM process parameters on raster level geometric features and structural properties of bioresorbable constructs. The development of an open architecture custom multi-process 3D printer employed for fabricating bioscaffolds and test structures is discussed. Bioresorbable polymers including a newly synthesized radiopaque polymer, poly (glycerol sebacate fumarate) gadodiamide (Rylar) and medical grade poly-L-lactic acid (PLLA) were investigated. In the first part, the effects of process parameters on raster geometry were investigated to aid in the fabrication of structures with improved geometric features …
Numerical Study Of Droplet Evaporation,
2017
University of Texas at Arlington
Numerical Study Of Droplet Evaporation, Ritul Gandhi
Mechanical and Aerospace Engineering Theses - Archive
Droplet evaporation plays a vital role in various engineering fields such as air/fuel premixing, inkjet printing and many more. The high rate of power dissipation from the integrated circuits and chips of electronic devices creates a need for cooling it to achieve their optimal functionality. The high rate of cooling can be achieved by thin film evaporation of water by phase change as compared to the air cooling methods. Therefore, the study of droplet evaporation is necessary to understand the underlying physics and effects of different parameters on cooling performance. Numerical study of droplet evaporation has been done by using …
Space Launch Vehicle Design: Conceptual Design Of Rocket Powered, Vertical Takeoff, Fully Expendable And First Stage Boostback Space Launch Vehicles,
2017
University of Texas at Arlington
Space Launch Vehicle Design: Conceptual Design Of Rocket Powered, Vertical Takeoff, Fully Expendable And First Stage Boostback Space Launch Vehicles, David Michael Woodward
Mechanical and Aerospace Engineering Theses - Archive
Engineering design can be broken down into three phases: conceptual design, preliminary design, and detailed design. During the conceptual design phase, several potential configurations are studied towards the identification of the baseline vehicle. Although the least amount of detail is known about the design during the early conceptual design phase, the decisions made during this phase lock in major features effecting life-cycle cost and overall product success. As the next big space race begins, it is critically important to have a readily available tool for launch vehicle designers that is intuitive to use, easy to modify, cost effective, and provides …
