Engineering Commons^™

The Effects Of Simplifications On Isolated Wheel Aerodynamics, Sammy Diasinos, Tracie Barber, Graham Doig

Aerospace Engineering

In order to study the aerodynamic forces and flow features of rotating wheels, compromises and simplifications are often made in wind tunnel testing, and more frequently so in numerical modelling. A CFD approach similar to that commonly used in industry was utilised to investigate common assumptions involving; the influence of geometric fidelity in wheel hub regions, ground representation, the modelling of the contact patch, and the effects of rotation on separation. It was found that the separation and wake characteristics were strongly influenced by the rotation of the wheel; the separation point changed by as much as 90% compared to …

Brief Look At The Environment Of Space, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "Brief Look at the Environment of Space" from September 10, 2015.

Lessons For Life, Story Musgrave

The Transdisciplinary STEAM+ Journal

This piece explores the creation of character and talent through a wide diversity of education and experience.

Design Of High-Area-Ratio Nozzle Contours Using Circular Arcs, K. Schomberg, J. Olsen, Graham Doig

Aerospace Engineering

A method using circular arcs to generate the divergence contour in a supersonic nozzle is presented. Comparison of the arc-based geometry with existing nozzle contours demonstrated that an average decrease in axial length of 7.5% can be expected when the arc-based design method is applied to a core stage nozzle. Two arc-based and conventional nozzles were evaluated numerically across the pressure operating range of a core stage engine to compare calculated thrust and separation characteristics with existing data. The length-weighted thrust coefficient was increased by 0.3–1.8% in the arc-based design in both configurations. Separated flow characteristics were compared using contours …

Experimental Investigations Of Dusty Spacecraft Charging At The Lunar Terminator, Kevin Chou, William Yu, Daoru Frank Han, Joseph J. Wang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An experimental investigation is conducted to understand the I-V characteristics and floating potential of a surface covered by varying amounts of dust in a plasma environment similar to that at the lunar terminator. I-V curves are measured to determine dust coverage effects on surface charging, and a non-contacting electrostatic voltmeter is used to measure dust surface charging. Results show that as dust coverage increases, the electric field created between the dust surface layer and conducting surface layer increases the possibility of arcing and breakdown.

Modeling And Test Of The Efficiency Of Electronic Speed Controllers For Brushless Dc Motors, Clayton R. Green

Master's Theses

Small electric uninhabited aerial vehicles (UAV) represent a rapidly expanding market requiring optimization in both efficiency and weight; efficiency is critical during cruise or loiter where the vehicle operates at part power for up to 99% of the mission time. Of the four components (battery, motor, propeller, and electronic speed controller (ESC)) of the electric propulsion system used in small UAVs, the ESC has no accepted performance model and almost no published performance data. To collect performance data, instrumentation was developed to measure electrical power in and out of the ESC using the two wattmeter method and current sense resistors; …

Premature Allocation Of Program Requirements To Suppliers, Bohdan W. Oppenheim

Systems Engineering Faculty Works

The paper presents a discussion of the difficulties of formulating stable requirements early in complex engineering programs, and the severe consequences on program execution. The problems are caused by the need to seek political and funding support for the program. Formal classical Systems Engineering (SE) and Program Management (CSEPM) methodology is based on the assumption that the knowledge to anticipate all interfaces and create good requirements exists early in the program, and it is only a matter of working out the details to build extremely complex devices such as satellites, aircraft, refineries, nuclear power plants and high speed rail. The …

The Rapidly Reconfigurable Research Cockpit, Richard Joyce

Link Foundation Modeling, Simulation and Training Fellowship Reports

The goal of the Rapidly Reconfigurable Research Cockpit (R3C) project is to create and evaluate a novel approach for aviation simulators. Our concept combines a virtual reality visual environment with the tactile feedback typically found in early stage mockups. A low cost, easily modified, yet geometrically accurate cockpit panel (fabricated using 3D printing, for example) can be used while the pilot/operator wears a head-mounted display providing the visual overlay of the simulator.

Thermal Earth Resource Monitoring Instrument (Thermi) Size, Weight And Power (Swap) Reduction, T. Newswander, Z. Bergen, J. Hancock, S. Hansen, A. Shumway, J. Stauder, D. Williams

Space Dynamics Laboratory Publications

The Thermal Earth Resource Monitoring Instrument (THERMI) has been designed to meet stringent Landsat heritage requirements with reduced size, weight and power (SWaP). The instrument design provides Earth resource monitoring through the use of two long-wave infrared bands that measure the land surface temperatures. These bands are especially valuable for monitoring water resources and water use. Instrument subsystems, including electronics, cryocooler, thermal management, optical telescope assembly, focal plane module, in-flight calibrator, and scene select mirror were studied and conceptually designed to reduce overall THERMI SWaP. Reductions in SWaP make it possible for THERMI to fit on a small satellite bus …

Phase Change Cells And The Verification Of Gallium As A Thermal Calibration Reference In Space, Harri Latvikoski, Gail E. Bingham, T. Shane Topham, Igor Podolski

Space Dynamics Laboratory Publications

The validation of models of global climate change and accurate measurement of the atmosphere and surface temperatures require that orbital sensors have low drift rates, and are monitored or regularly recalibrated by accepted standards. Phase change materials (PCM), such as those that make up the ITS-90 standard, are the basis for international commerce and have been suggested for monitoring and recalibration of orbital temperature sensors. Space Dynamics Laboratory (SDL) and its partners have been developing miniaturized phase change reference technologies that could be deployed on an orbital blackbody for nearly a decade. A significant part of this effort has been …

Contributions Of Mass And Bond Energy Difference And Interface Defects On Thermal Boundary Conductance, Nicholas A. Roberts, Changjin Choi

Mechanical and Aerospace Engineering Faculty Publications

The impact of mass and bond energy difference and interface defects on thermal boundary conductance (TBC) is investigated using non-equilibrium molecular dynamics (NEMD) with the Lennard-Jones (L-J) interatomic potential. Results show that the maximum TBC is achieved when the mass and bond energy of two dissimilar materials are matched, although the effective thermal conductivity is not necessarily a maximum due to the contributions of the thermal conductivity of the constituent materials. Mass and bond energy differences result in a mismatch between phonon dispersions, limiting high frequency phonon transport at the interface. This frequency mismatch is defined by a frequency ratio, …

Development Of Cpanel, An Unstructured Panel Code, Using A Modified Tls Velocity Formulation, Christopher R. Satterwhite

Master's Theses

The use of panel codes in the aerospace industry dates back many decades. Recent advances in computer capability have allowed them to evolve, both in speed and complexity, to provide very quick solutions to complex flow fields. By only requiring surface discretization, panel codes offer a faster alternative to volume based methods, delivering a solution in minutes, as opposed to hours or days. Despite their utility, the availability of these codes is very limited due to either cost, or rights restrictions.

This work incorporates modern software development practices, such as unit level testing and version control, into the development of …

A Brief History Of Space - Sse 120 Session 1, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on "A Brief History of Space - Session 01" from August 30, 2015.

Medium-Range Forecast Of The Arctic Sea-Ice Cover Using The Satellite Observation Data, Kimura Noriaki

ShipArc 2015 Conference

No abstract provided.

Use Of Satellite Sar Observations Integrated In Arctic Maritime Situational Awareness, Hans Eilif Larsen

ShipArc 2015 Conference

No abstract provided.

A Brief History Of Space - Sse 120 Questions 01, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on "A Brief History of Space - Questions 01" from August 26, 2015.

A Brief History Of Space - Sse 120 Questions 02, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on "A Brief History of Space - Questions 02" from August 25, 2015.

A Brief History Of Space - Sse 120 Questions 04, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on "A Brief History of Space - Questions 04" from August 25, 2015.

A Brief History Of Space - Sse 120 Questions 03, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on "A Brief History of Space - Questions 03" from August 25, 2015.

What Is Orbital Debris?, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on "What is Orbital Debris?" from August 24, 2015.

Brief Look At The Environment Of Space, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "Brief Look at the Environment of Space" from August 24, 2015.

Shape Optimization Of Busemann-Type Biplane Airfoil For Drag Reduction Under Nonlifting And Lifting Conditions Using Genetic Algorithms, Yi Tian

McKelvey School of Engineering Graduate Student Theses & Dissertations

The focus of this thesis is on the shape optimization of the Busemann-type biplane airfoil for drag reduction under both nonlifting and lifting conditions using genetic algorithms. The concept of the Busemann-type biplane airfoil was first introduced by Adolf Busemann in 1935. Under its design condition at a specific supersonic flow speed, the Busemann biplane airfoil eliminates all wave drag due to its symmetrical biplane configuration; however it produces zero lift. Previous research has shown that the original Busemann biplane airfoil design has a poor performance under off-design conditions as well. In order to solve this problem of zero lift …

Application Of Wray-Agarwal Model To Turbulent Flow In A 2d Lid-Driven Cavity And A 3d Lid-Driven Box, Hakop J. Nagapetyan

McKelvey School of Engineering Graduate Student Theses & Dissertations

In this thesis, various turbulence models are used for simulating internal vortical flow, both turbulent and laminar, with large recirculation by considering the flow in a 2-D lid-driven square cavity and a 3-D lid driven cubic box. The accuracy of the newly developed Wray-Agarwal (WA) one equation turbulence model is compared against two well-known industry standard turbulence models; the Spalart-Allmaras (SA) and the Shear-Stress-Transport (SST) k-ω models. The simulations are performed by numerically solving the Reynolds-Averaged Navier-Stokes (RANS) equations in conjunction with WA, SA and SST k-ω models and comparing the results with the available experimental data and Large Eddy …

Dynamic Characteristics Of Biologically Inspired Hair Receptors For Unmanned Aerial Vehicles, Manohar Chidurala

LSU New Orleans Theses and Dissertations

The highly optimized performance of nature’s creations and biological assemblies has inspired the development of their engineered counter parts that can potentially outperform conventional systems. In particular, bat wings are populated with air flow hair receptors which feedback the information about airflow over their surfaces for enhanced stability and maneuverability during their flight. The hairs in the bat wing membrane play a role in the maneuverability tasks, especially during low-speed flight. The developments of artificial hair sensors (AHS) are inspired by biological hair cells in aerodynamic feedback control designs. Current mathematical models for hair receptors are limited by strict simplifying …

Orbital Debris Mitigation Policy And Unique Challenges For Small Satellites, J. C. Liou, David Jarkey

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by J. C. Liou and David Jarkey titled "Orbital Debris Mitigation Policy and Unique Challenges for Small Satellites" at the Small Satellite Conference on August 10, 2015.

Overview Of The Orbital Debris Problem, J. C. Liou

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by J. C. Liou titled "Overview of the Orbital Debris Problem" at the Small Satellite Conference on August 10, 2015.

Characterizing Strain Accumulation, Residual Stress, And Microstructure Of Additive Manufactured Materials, Hannah K. Woods, Todd A. Book, Catalina Parada, Michael D. Sangid

The Summer Undergraduate Research Fellowship (SURF) Symposium

Additive Manufacturing (AM) is a rapidly evolving fabrication technology beneficial for its cost-saving potential to produce complex, low-volume shapes. However, AM materials are currently limited to nonstructural applications due to variability in their structural integrity, particularly their fatigue lives. IN718, Ti64, and Al10MgSi specimens manufactured by Direct Metal Laser Sintering (DMLS) were characterized based on variation of post-processing techniques and build direction. To understand the impact of each variable, surface roughness, hardness, residual stresses, microstructure, and strain accumulation in response to Low Cycle Fatigue (LCF) were studied. The use of Electron Backscatter Diffraction (EBSD) provided grain orientation and grain size …

Refinement And Validation Of A Real-Time Airborne System For Remotely Sensing Ocean Surface Using Communication Satellite Signals, Benjamin R. Nold, Han Zhang, James L. Garrison

The Summer Undergraduate Research Fellowship (SURF) Symposium

The ability to remotely sense ocean wave heights and wind speed by measuring the reflected Radio Frequency (RF) signals from the ocean’s surface has been demonstrated in previous research projects. The recording systems for these research projects collected and stored unmodified RF signals and then analyzed the data through post-processing. Several disadvantages to this approach include large requirements for data storage and lengthy post-processing time. To assist in the creation of a suitable platform for an airplane-based application, a new system was designed which features real-time processing of the RF signals. This system captures two RF signals in the 2.4 …

Assessment Of Critical Technologies For Gas Turbine Engines Using Numerical Tools, Vinicius Pessoa Mapelli, Guillermo Paniagua, Jorge Sousa

The Summer Undergraduate Research Fellowship (SURF) Symposium

In 2014 gas turbine engine has reached a market value of 82.5 billion dollars, of which 59.5% are related to aircraft propulsion. The continuous market expansion attracts more and more the interest of researchers and industries towards the development of accurate numerical techniques to model thermodynamically the entire engine. This practice allows a performance and optimization analysis before the actual experimental testing, reducing the time and required investment in the design of a new engine. In this paper, a recently developed open source numerical tool named “Toolbox for the Modeling and Analysis of Thermodynamic Systems” (T-MATS) is used to assess …

Dsmc Simulation Of Microstructure Actuation By Knudsen Thermal Force, Aaron Pikus, Israel Sebastiao, Andrew Strongrich, Alina Alexeenko

The Summer Undergraduate Research Fellowship (SURF) Symposium

In many industrial and research applications there is a need for vacuum sensors with higher accuracy and spatial resolution than what is currently available. Examples of target applications include high-altitude platforms, satellites and in-vacuum manufacturing processes such as freeze-drying of food and pharmaceuticals. In this connection, a novel pressure sensor, named Microelectromechanical In-plane Knudsen Radiometric Actuator (MIKRA), has been developed by at Purdue University. MIKRA is based on Knudsen thermal forces generated by rarefied flow driven by thermal gradients within the microstructure Thus, the goal of this work is to model the rarefied gas flow in the MIKRA sensor under …