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 …
A Methodology For Topology And Lattice Structure Optimization Of A Cargo Drone Motor Mount,
2017
University of Texas at Arlington
A Methodology For Topology And Lattice Structure Optimization Of A Cargo Drone Motor Mount, Nagadurga Srinivas Sripada
Mechanical and Aerospace Engineering Theses - Archive
This work discusses a CAE driven methodology for designing a lightweight component by performing structural configuration on a given package space, creating a closed surface along this configuration using an interactive geometric modeling tool, and lastly generating lattice members that provide the required stiffness for the structure. The design process is explained starting with topology optimization performed on a single block with specific design constraints. It describes the effect of different parameters on the optimized results and how to analyze these results based on a given volume fraction constraint with the objective of minimizing the compliance. It then talks about …
Region Based Convolutional Neural Networks For Object Detection And Recognition In Adas Application,
2017
University of Texas at Arlington
Region Based Convolutional Neural Networks For Object Detection And Recognition In Adas Application, Sachit Kaul
Mechanical and Aerospace Engineering Theses - Archive
Object Detection and Recognition using Computer Vision has been a very interesting and a challenging field of study from past three decades. Recent advancements in Deep Learning and as well as increase in computational power has reignited the interest of researchers in this field in last decade. Implementing Machine Learning and Computer Vision techniques in scene classification and object localization particularly for automated driving purpose has been a topic of discussion in last half decade and we have seen some brilliant advancements in recent times as self-driving cars are becoming a reality. In this thesis we focus on Region based …
The Design And Linearization Of Flow Control Device And Pressure Forces On Valve,
2017
University of Texas at Arlington
The Design And Linearization Of Flow Control Device And Pressure Forces On Valve, Penchala Sumanth Reddy Challa
Mechanical and Aerospace Engineering Theses - Archive
Emerging technologies are pushing the limits by reducing the size of the nodes, raising the heat densities of packages thereby demanding better thermal management. The cooling power requirement increases drastically when air is used as the cooling medium in high power density servers as air has a low heat transfer coefficient. Very viable replacements for air as the cooling medium are water and oil. Oil is not as widely used as it has its own disadvantages when compared to water. Water has appreciably higher heat transfer coefficient, which helps it to remove heat from the server at a much faster …
Computational Model For Steady State Simulation Of A Solid Oxide Fuel Cell (Sofc) Planar Stack Model Undergoing Reforming Process,
2017
University of Texas at Arlington
Computational Model For Steady State Simulation Of A Solid Oxide Fuel Cell (Sofc) Planar Stack Model Undergoing Reforming Process, Vaibhav Vijay Indulkar
Mechanical and Aerospace Engineering Theses - Archive
Solid Oxide Fuel Cell (SOFC), is a clean and low-pollution technology of generating power of high efficiency. Its applicability for both stationery and transportation power generation systems, adaptability for wide range fuel sources, as wells its process of direct conversion of fuel to energy make it an important source of power generation. An effective design of sub-systems or individual components play a key role in overall working of a plant. Thus, critical analysis at the component level is of importance for the overall plant efficiency. In the present study a heat transfer model of a planar SOFC stack to be …
Reliability Assessment Of Solder Joint Using Bga Package – Megtron 6 Versus Fr4 Printed Circuit Boards Using Drop Testing,
2017
University of Texas at Arlington
Reliability Assessment Of Solder Joint Using Bga Package – Megtron 6 Versus Fr4 Printed Circuit Boards Using Drop Testing, Pradnya Chandrakant Mundhe
Mechanical and Aerospace Engineering Theses - Archive
In electronic industry Ball grid array (BGA) package, surface mount technology has been used widely, due to its robust design, high density connections and improved performance. In surface mount technology, solder joints are used to interconnect package and PCB board assembly. High frequency laminates use in PCB boards provides excellent performance for high speed, frequency devices. Nelco 4000-13EPSI, Panasonic Megtron 6, and Rogers 4350B are few popular laminates. Component size reduction and structural complexity because of increasing number of transistors are making it very difficult to protect the packages from mechanical, thermal, and electrical damage. Difference in material properties between …
Computational Morphology Modelling And Mixed Mode Fracture Analysis Of Zrb2/Sic Based Ceramic Nano-Materials Using Molecular Dynamics,
2017
University of Texas at Arlington
Computational Morphology Modelling And Mixed Mode Fracture Analysis Of Zrb2/Sic Based Ceramic Nano-Materials Using Molecular Dynamics, Krutarth Shaileshkumar Patel
Mechanical and Aerospace Engineering Theses - Archive
Transition metal carbides, nitrides, and borides are a group of Ultra High-Temperature Ceramic (UHTC). Owing to their remarkable properties of the high melting point, high thermal conductivity and excellent strength at elevated temperature ZrB2 based composites are of high interest for use in the high-temperature environment. It is proved that addition of SiC in ZrB2 can advance composite’s oxidation resistance, mechanical strength, fracture toughness and sintering behavior. Firstly, molecular dynamics is used to simulate crack growth under mixed mode loading in Al, SiC, and ZrB2 single crystals by considering inclined crack under uniaxial tension and crack growth angle are compared …
A Study On The Turbulence Characteristics And Mixing Performance Of Streamwise Vortex Interactions In Supersonic Flow,
2017
University of Texas at Arlington
A Study On The Turbulence Characteristics And Mixing Performance Of Streamwise Vortex Interactions In Supersonic Flow, Cody R. Ground
Mechanical and Aerospace Engineering Dissertations - Archive
The scramjet engine offers the unique capability to enable sustained airbreathing flight at hypersonic speeds. However, in order to reach its full application potential, further technological maturation of several system level components is necessary. One such component is the fuel injection system. The flow conditions characteristic of the scramjet combustor are such that the rate-limiting step in the fuel injection/mixing/combustion process is the mixing of the fuel and air. For this reason, the fuel injection system must be designed with the goal of enhancing the rate of fuel/air mixing. One method that has shown potential to enhance fuel/air mixing in …
Investigation On Metal-Composite Hybrid Flywheels Using Finite Element Method,
2017
University of Texas at Arlington
Investigation On Metal-Composite Hybrid Flywheels Using Finite Element Method, Ching Huai Wang
Mechanical and Aerospace Engineering Theses - Archive
This research is aimed to investigate the kinetic energy storage of a hybrid metal-composite flywheel rotating at high speeds. The upper limit of energy, which flywheel can supply, is restricted by the strength of material because both energy and stress are proportional to the density of the material and the square of the velocity. Metal flywheels operate at lower rotational speed and supply less energy than the composite flywheels. Composite flywheels have a very high density per unit mass, but lower energy density per unit of the design volume. The ultra-high speed of composite flywheels creates some engineering challenges such …
Reliability Assessment Of Solder Joint Interconnects Of Bga Package-Megtron Series Under Power Cycling,
2017
University of Texas at Arlington
Reliability Assessment Of Solder Joint Interconnects Of Bga Package-Megtron Series Under Power Cycling, Mahesh Pallapothu
Mechanical and Aerospace Engineering Theses - Archive
Solder joint interconnects are the second level assembly in surface mount interconnection technology. Mismatch in the coefficient of thermal expansion (CTE) between package and substrate or PCB creates failure in solder joints such as excessive warpage, low-k dielectric cracking, solder mask cracking and bump cracking. Conventional accelerated thermal cycling tests are performed to evaluate the Solder Joint Reliability (SJR). But, in everyday application, the package is subjected to Power cycling. Power cycling is the phenomenon where the package experiences non-uniform temperature distribution in the package with the chip as an internal heat generating source when an electronic device is turned …
Effective Thermal Conductivity Of Porous Media By Inverse Heat Transfer Analysis,
2017
University of Texas at Arlington
Effective Thermal Conductivity Of Porous Media By Inverse Heat Transfer Analysis, Oscar Javier Ii Fabela
Mechanical and Aerospace Engineering Theses - Archive
This research describes the application of inverse analysis to estimate the thermal conductivity of a porous material using temperature measurements at the surfaces. Finite volume analysis code is implemented in MATLAB and it is utilized to solve the steady state, axisymmetric heat transfer governing energy equation. The analysis code is coupled with a numerical optimization method and utilized to predict thermal conductivity using the measurements. An experimental setup was developed to test a porous media composed of a mixture of small pellets and air. In experiments, temperature is measured at outer surface of copper tube. These data, serves as input …
Real-Time Minimum Jerk Optimal Trajectory Synthesis And Tracking For Ground Vehicle Applications,
2017
University of Texas at Arlington
Real-Time Minimum Jerk Optimal Trajectory Synthesis And Tracking For Ground Vehicle Applications, Naga Venkata Murali Veerapaneni
Mechanical and Aerospace Engineering Theses - Archive
Research on wheeled mobile robots has been an active research field for several decades with focus on the problems of stability, maneuverability and control. The trajectory generation for wheeled mobile robots is usually handled by considering a smooth function satisfying the boundary conditions. Even though this problem is well posed for several function classes, the real issue occurs in generating a feasible trajectory for the robot which takes into account the constraints of the system. Another problem from the control system perspective is, whether the derived controller is stable for the entire trajectory span to track the given trajectory. The …
