Aerospace Engineering Commons^™

Louver And Effusion Cooling Heat Transfer For A Double Wall Effusion Plate With Impingement Jet Array Coolant Supply, Sneha Reddy Vanga, Phillip M. Ligrani, Joseph Knox, Federico Liberatore, Rajeshriben Patel, Ying-Hsiang Ho

PRC-Affiliated Research

Louver slot cooling is employed, which consists of an aligned collection of film cooling holes, contained within a specially-designed device which concentrates, and directs the coolant from a slot, so that cooling air then advects as a layer downstream along the test surface. This louver-supplied coolant is then supplemented by coolant which emerges from different rows of downstream film cooling holes. Coolant for both cooling arrangements is supplied using an array of impingement jets. Experimental data are provided for a mainstream Reynolds number Rems range of 168,000–181,000. Full-coverage film cooling initial blowing ratio values are 2.5, 3.2, 4.4, and 5.2, …

Automated Residential Energy Audits Using A Smart Wifi Thermostat-Enabled Data Mining Approach, Abdulrahman Alanezi, Kevin Hallinan, Kefan Huang

Mechanical and Aerospace Engineering Faculty Publications

Smart WiFi thermostats, when they first reached the market, were touted as a means for achieving substantial heating and cooling energy cost savings. These savings did not materialize until additional features, such as geofencing, were added. Today, average savings from these thermostats of 10–12% in heating and 15% in cooling for a single-family residence have been reported. This research aims to demonstrate additional potential benefit of these thermostats, namely as a potential instrument for conducting virtual energy audits on residences. In this study, archived smart WiFi thermostat measured temperature data in the form of a power spectrum, corresponding historical weather …

Determination Of The Feature Resolution Of Processed Image Data Via Statistical Analysis, Joseph S. Indeck, Jesus O. Mares Jr., James P. Vitarelli, Kavan Hazeli

PRC-Affiliated Research

A method is presented to determine the feature resolution of physically relevant metrics of data obtained from segmented image sets. The presented method determines the best-fit distribution curve of a dataset by analyzing a truncated portion of the data. An effective resolvable size for the metric of interest is established when including parts of the truncated dataset results in exceeding a specified error tolerance. As such, this method allows for the determination of the feature resolution regardless of the processing parameters or imaging instrumentation. Additionally, the number of missing objects that exist below the resolution of the instrumentation may be …

Indirect Model Reference Adaptive Control With Online Parameter Estimation, Jovan Bruce

Doctoral Dissertations and Master's Theses

Over the years, parameter estimation has focused on approaches in both the time and frequency domains. The parameter estimation process is particularly important for aerospace vehicles that have considerable uncertainty in the model parameters, as might be the case with unmanned aerial vehicles (UAVs). This thesis investigates the use of an Indirect Model Reference Adaptive Controller (MRAC) to provide online, adaptive estimates of uncertain aerodynamic coefficients, which are in turn used in the MRAC to enable an aircraft to track reference trajectories. The performance of the adaptive parameter estimator is compared to that of the Extended Kalman Filter (EKF), a …

Investigation Of Trajectory And Control Designs For A Solar Sail To The Moon, Michelle Nadeau

Doctoral Dissertations and Master's Theses

NASA’s Artemis program and other government and commercial projects are working toward establishing a sustainable human presence on the moon. This thesis investigates the technical feasibility of a solar sail-based spacecraft (sailcraft) as a low-cost method of delivering cargo or science instruments to the moon and demonstrates how this sailcraft could be controlled to change its orbit. The concept is a low-cost, commercial launch vehicle-deployable, CubeSat-based sailcraft with a square sail, assumed attitude control, and a small payload traversing from low-Earth orbit toward the moon with zero propellant use. In this thesis, methods for sailcraft to increase altitude, the trajectory …

Space Exploration: Nasa Investment Into The Private Space Sector And Public Opinion, Brooke Ziegenhagen

Senior Theses

The space exploration industry has entered a new era with companies such as SpaceX and Blue Origin leading the way to the privatization of space. This paper examines public opinion regarding the source of space exploration funding and proposes possible motivations for these sentiments. This is followed by an assessment on NASA’s investment trends into the commercial space industry. Both probes review the past decade, to reveal the public-private relationship in this new era and finally, conclude whether or not public opinion plays a role in the degree of NASA investment and what that role may be.

The Impact Of Uas On The Passenger Airline Industry, Matthew Whitten

Senior Honors Theses

This study seeks to cover the state of modern autonomous unmanned aerial systems (UAS) integration into commercial aviation, the future applications of the technology in the airline industry, and the roadblocks currently hindering its integration into passenger operations. Although great advancements are being made in the field, technological developments, economic impact, legal restrictions, airline cost, and public perception stand in the way of the full adaptation of autonomous technology into everyday passenger operations. However, technology is rapidly developing, perhaps allowing for the possibility of autonomous air travel even today, but there are likely years of refinement before regulators, executives, and …

A Comparative Study Between 6 Degree-Of-Freedom Trajectory Model And Modified Point Mass Trajectory Model Of Spinning Projectiles, Ange Du

Doctoral Dissertations and Master's Theses

For spinning projectiles, the 6 Degree-of-Freedom model can closely capture their trajectories with high accuracy and details. However, it comes with the drawbacks of long computation time and needing many aerodynamic coefficients which can be hard to obtain. The Modified Point Mass Trajectory Model was introduced as a simplified solution. This work compares them with each other, and with some more conventional methods. A program is developed to simulate and visualize trajectories. With some augmentations, the Modified Point Mass model is able to generate comparable results in most cases, but not including special cases such as when the projectile is …

A New Method For Estimating The Physical Characteristics Of Martian Dust Devils, Shelly Cahoon Mann

Mechanical & Aerospace Engineering Theses & Dissertations

Critical to the future exploration of Mars is having a detailed understanding of the atmospheric environment and its potential dangers. The dust devil is one of these potential dangers. The transport of dust through saltation is believed to be the driving mechanism responsible for Martian weather patterns. The two primary mechanisms for dust transport are dust storms and dust devils. Dust devils on Mars are a frequent occurrence with one in five so called giant dust devils being large enough to leave scars on the surface that are visible from space. Due to the thin atmosphere, winds of 60 mph …

A Model-Based Systems Engineering Approach To E-Vtol Aircraft And Airspace Infrastructure Design For Urban Air Mobility, Heidi Selina Glaudel

Mechanical & Aerospace Engineering Theses & Dissertations

This paper serves to contribute to Model-Based Systems Engineering (MBSE) by following the NASA Systems Engineering Handbook framework for a Systems Engineering (SE) design approach to an Electric Vertical Takeoff and Landing (e-VTOL) aircraft and the incorporating airspace infrastructure. The focus of this study is, by using the MBSE model created, to capture the technical requirements definition and design intent of the vehicle and airspace inclusive of community specific knowledge derived from the Federal Aviation Administration (FAA) NextGen Urban Air Mobility (UAM) Concept of Operations (ConOps) version 1.0. The stakeholder requirements derived from the FAA UAM NextGen ConOps will form …

Failure Of Ultra-High Molecular Weight Polyethylene Yarns (Uhmpwe) Under Transverse Loading Using Different Indenter Geometries, Karan Shah

Theses and Dissertations

Ultra-high molecular weight polyethylene (UHMWPE) Dyneema® SK-76 fibers are widely used in personnel protection systems. Transverse ballistic impact onto these fibers results in complex multiaxial deformation modes such as axial tension, axial compression, transverse compression, and transverse shear. Previous impact studies on high performance yarns and quasi-static transverse loading of single fibers using different indenter geometries show premature failure of yarns and single fiber caused by the degradation of tensile failure strain due to the presence of such multi-axial deformation modes. However, there is a dearth of failure criterion in the literature for ballistic applications that considers the contribution of …

Improved Strain Gage Instrumentation Strategies For Rotorcraft Blade Measurements, Timothy S. Davis

Mechanical & Aerospace Engineering Theses & Dissertations

In this work, a new strategy is presented to wire, calibrate, and measure strain gages for rotor blade testing that will provide more information and is robust to individual gage loss. The additional information can be used in several ways. including reducing redundancy, offering rapid identification of damage locations, and in some cases reducing risk allowing tests to continue to collect calibrated data after one or more sensors have failed. This strategy replaces the classical four-gage full Wheatstone bridge with four separately wired quarter bridges that are combined into a full bridge in the data acquisition system using a calculated …

Ion Gnss Software-Defined Radio Metadata Standard, Sanjeev Gunawardena, Thomas Pany, James Curran

Faculty Publications

The past several years have seen a proliferation of software‐defined radio (SDR) data collection systems and processing platforms designed for or applicable to satellite navigation (satnav) applications. These systems necessarily produce datasets in a wide range of different formats. To correctly interpret this SDR data, essential information such as the packed sample format and sampling rate is needed. Communicating this metadata between creators and users has historically been an ad‐hoc, cumbersome, and error‐prone process. To address this issue, the satnav SDR community developed a metadata standard and normative software library to automate this process, thus simplifying the exchange of datasets …

Wind Tunnel Wake Generator, Carl Pickl, James L. Rutledge, Marc D. Polanka, Brian Crabtree, Christopher Harkless

AFIT Patents

A wake generator for placement in a wind tunnel between a wind source and a test object for generating a predetermined wake pattern, comprising: a first frame member comprising a first track formed thereon, the first track having a rounded first side and a flat second side; a mounting plate disposed within a perimeter of the first track, the mounting plate rotatable relative to the first frame member about a first axis; and a plurality of bars slidably engaged to the mounting plate and structurally configured to traverse along the first track when the mounting plate is rotated about the …

Sharing Airspace: Simulation Of Commercial Space Horizontal Launch Impacts On Airlines And Finding Solutions, Janet K. Tinoco, Chunyan Yu, Rodrigo Firmo, Carlos Alberto Castro, Mohammad Moallemi, Ryan Babb

Publications

Commercial space transportation is becoming more affordable and accessible. Consequently, we expect to see significant expansion of commercial space launch activities in the coming decade. As space vehicles travel through airspace during the launch and re-entry stages, they potentially disrupt the regular operations of traditional users. This paper estimates the potential economic and operational impacts of commercial space horizontal launch activities on airlines under various launch scenarios using predictive fast-time simulation modeling, focusing on Cecil Air and Space Port in Jacksonville (Florida) and the rules governing the national airspace system (NAS) in the United States. Our results indicate that the …

Development Of A Hybrid Particle Continuum Solver, Anthony J. Gay

Master's Theses

When simulating complex flows, there are some physical situations that exhibit large fluctuations in particle density such as: planetary reentry, ablation due to arcing, rocket exhaust plumes, etc. When simulating these events, a high level of physical accuracy can be achieved with kinetic methods otherwise known as particle methods. However, this high level of physical accuracy requires large amounts of computation time. If the simulated flow is in collisional equilibrium, then less computationally intensive continuum methods, otherwise known as fluid methods, can be utilized. Hybrid Particle-Continuum (HPC) codes attempt to blend particle and fluid solutions in order to reduce computation …

A Method For Visualizing The Structural Complexity Of Organizational Architectures, Jacob Michael B. King

Master's Theses

To achieve a high level of performance and efficiency, contemporary aerospace systems must become increasingly complex. While complexity management traditionally focuses on a product’s components and their interconnectedness, organizational representation in complexity analysis is just as essential. This thesis addresses this organizational aspect of complexity through an Organizational Complexity Metric (OCM) to aid complexity management. The OCM augments Sinha’s structural complexity metric for product architectures into a metric that can be applied to organizations. Utilizing nested numerical design structure matrices (DSMs), a compact visual representation of organizational complexity was developed. Within the nested numerical DSM are existing organizational datasets used …

Development Of An Infrared Thermography System To Measure Boundary Layer Transition In A Low Speed Wind Tunnel Testing Environment, Damien Horton

Master's Theses

The use of infrared thermography for boundary layer detection was evaluated for use in the Cal Poly Low Speed Wind Tunnel (LSWT) and recommendations for the successful use of this technique were developed. In cooperation with Joby Aviation, an infinite wing model was designed, manufactured and tested for use in the LSWT. The wing was designed around a custom airfoil profile specific for this project, where the nearly-flat pressure gradient at a zero pitch angle would delay the chordwise onset of boundary layer transition. Steady-state, RANS numerical simulations predicted the onset of transition to occur at 0.75 x/c for the …

Comparing Radiation Shielding Potential Of Liquid Propellants To Water For Application In Space, John Czaplewski

Master's Theses

The radiation environment in space is a threat that engineers and astronauts need to mitigate as exploration into the solar system expands. Passive shielding involves placing as much material between critical components and the radiation environment as possible. However, with mass and size budgets, it is important to select efficient materials to provide shielding. Currently, NASA and other space agencies plan on using water as a shield against radiation since it is already necessary for human missions. Water has been tested thoroughly and has been proven to be effective. Liquid propellants are needed for every mission and also share similar …

Data-Driven Cfd Scaling Of Bioinspired Mars Flight Vehicles For Hover, Jeremy A. Pohly, Chang-Kwon Kang, Brian D. Landrum, James E. Bluman, Hikaru Aono

PRC-Affiliated Research

One way to improve our model of Mars is through aerial sampling and surveillance, which could provide information to augment the observations made by ground-based exploration and satellite imagery. Flight in the challenging ultra-low-density Martian environment can be achieved with properly scaled bioinspired flapping wing vehicle configurations that utilize the same high lift producing mechanisms that are employed by insects on Earth. Through dynamic scaling of wings and kinematics, we investigate the ability to generate solutions for a broad range of flapping wing flight vehicles with masses ranging from insects O(10−3) kg to the Mars helicopter Ingenuity O(100) kg. A …

Data-Driven Cfd Scaling Of Bioinspired Mars Flight Vehicles For Hover, Jeremy A. Pohly, Chang-Kwon Kang, Brian D. Landrum, James E. Bluman, Hikaru Aono

PRC-Affiliated Research

One way to improve our model of Mars is through aerial sampling and surveillance, which could provide information to augment the observations made by ground-based exploration and satellite imagery. Flight in the challenging ultra-low-density Martian environment can be achieved with properly scaled bioinspired flapping wing vehicle configurations that utilize the same high lift producing mechanisms that are employed by insects on Earth. Through dynamic scaling of wings and kinematics, we investigate the ability to generate solutions for a broad range of flapping wing flight vehicles with masses ranging from insects O(10−3) kg to the Mars helicopter Ingenuity O(100) kg. A …

Accelerated Controller Tuning For Wind Turbines Under Multiple Hazards, Aly Mousaad Aly, Milad Rezaee

Faculty Publications

During their lifecycle, wind turbines can be subjected to multiple hazard loads, such as high-intensity wind, earthquake, wave, and mechanical unbalance. Excessive vibrations, due to these loads, can have detrimental effects on energy production, structural lifecycle, and the initial cost of wind turbines. Vibration control by various means, such as passive, active, and semi-active control systems provide crucial solutions to these issues. We developed a novel control theory that enables semi-active controller tuning under the complex structural behavior and inherent system nonlinearity. The proposed theory enables the evaluation of semi-active controllers’ performance of multi-degrees-of-freedom systems, without the need for time-consuming …

Time-Dependent System Reliability Analysis With Second-Order Reliability Method, Hao Wu, Zhangli Hu, Xiaoping Du

Mechanical and Aerospace Engineering Faculty Research & Creative Works

System reliability is quantified by the probability that a system performs its intended function in a period of time without failures. System reliability can be predicted if all the limit-state functions of the components of the system are available, and such a prediction is usually time consuming. This work develops a time-dependent system reliability method that is extended from the component time-dependent reliability method using the envelope method and second-order reliability method. The proposed method is efficient and is intended for series systems with limit-state functions whose input variables include random variables and time. The component reliability is estimated by …

Design And Analysis Of Air-Stiffened Vacuum Lighter-Than-Air Structures, Ruben Adorno-Rodriguez

Theses and Dissertations

Lighter-than-air (LTA) systems have been developed for numerous applications and have taken several forms. Airships, aerostats, blimps, and balloons are all part of this family of systems, which uses Archimedes principle to achieve neutral and positive buoyancy in air by replacing an air volume with LTA gases. These lifting gases stiffen the otherwise compliant envelope structures, allowing them to sustain the pressure difference brought by the displaced air. The compliance of these structures is a byproduct of the weight requirement, materials and geometrical arrangement of which these structures are built from, typically resulting in dimensionalities that exhibit low or virtually …

Mechanical Properties And Performance Of A Novel Nano-Engineered Unitized Composite For Aerospace Systems, Benjamin C. Lam

Theses and Dissertations

Carbon nanotubes (CNTs) exhibit outstanding mechanical properties, such as exceptionally high tensile stiffness and strength, combined with excellent electrical and thermal characteristics. This research investigates the mechanical properties and performance of a newly developed hybrid nano-engineered composite. The carbon fiber/polymer matrix composite incorporates a forest of vertically aligned CNTs, called NanoStitch, between the prepreg plies. Basic tensile properties of both material systems were investigated for both on-axis [0/90] and off-axis [±45] fiber orientations at room temperature. Tension-tension fatigue tests were performed with a frequency of 1.0 Hz and a ratio of minimum stress to maximum stress of R= 0.05. Fatigue …

The Effects Of Remotely Piloted Aircraft Command And Control Latency During Within-Visual-Range Air-To-Air Combat, David Thirtyacre

Doctoral Dissertations and Master's Theses

The type of military missions conducted by remotely piloted aircraft continues to expand into all facets of operations including air-to-air combat. While future within-visual-range air-to-air combat will be piloted by artificial intelligence, remotely piloted aircraft will likely first see combat. The purpose of this study was to quantify the effect of latency on one-versus-one, within-visual-range air-to-air combat success during both high-speed and low-speed engagements. The research employed a repeated-measures experimental design to test the various hypothesis associated with command and control latency. Participants experienced in air-to-air combat were subjected to various latency inputs during one-versus-one simulated combat using a virtual-reality …

Adaptive Kriging Method For Uncertainty Quantification Of The Photoelectron Sheath And Dust Levitation On The Lunar Surface, Xinpeng Wei, Jianxun Zhao, Xiaoming He, Zhen Hu, Xiaoping Du, Daoru Han

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper presents an adaptive Kriging based method to perform uncertainty quantification (UQ) of the photoelectron sheath and dust levitation on the lunar surface. The objective of this study is to identify the upper and lower bounds of the electric potential and that of dust levitation height, given the intervals of model parameters in the one-dimensional (1D) photoelectron sheath model. To improve the calculation efficiency, we employ the widely used adaptive Kriging method (AKM). A task-oriented learning function and a stopping criterion are developed to train the Kriging model and customize the AKM. Experiment analysis shows that the proposed AKM …

A Reduced Order Model Of The Celestial Icosahedron As The Substructure For A Lighter Than Air Vehicle, Torin C. Quick

Theses and Dissertations

A finite element approach was used to investigate a novel reduced order model to determine the minimum structure dimensionality to support vacuum for a VLTAV. This modeling technique represented the individual segments of the substructure as curved beams with clamped radially-resisted boundary conditions. The full structure was then modeled as a bare structure and structure with skin to validate the results of the reduced order model. The beam geometry for the material Ultem 9085 was determined through this process leading to the 3-D printing of the structure. It was then experimentally tested under uniaxial compression complimented with a FEA model.

Ram Air-Turbine Of Minimum Drag, Raymond Akagi

Master's Theses

The primary motivation for this work was to predict the conditions that would yield minimum drag for a small Ram-Air Turbine used to provide a specified power requirement for a small flight test instrument called the Boundary Layer Data System. Actuator Disk Theory was used to provide an analytical model for this work.

Classic Actuator Disk Theory (CADT) or Froude’s Momentum Theory was initially established for quasi-one-dimensional flows and inviscid fluids to predict the power output, drag, and efficiency of energy-extracting devices as a function of wake and freestream velocities using the laws of Conservations of Mass, Momentum, and Energy. …

Optimizing A Bank Of Kalman Filters For Navigation Integrity, Luis E. Sepulveda

Theses and Dissertations

Alternative navigation is an area of research which employs a variety of sensor technologies to provide a navigation solution in Global Navigation Satellite System degraded or denied environments. The Autonomy and Navigation Technology Center at the Air Force Institute of Technology has recently developed the Autonomous and Resilient Management of All-source Sensors (ARMAS) navigation framework which utilizes an array of Kalman Filters to provide a navigation solution resilient to sensor failures. The Kalman Filter array size increases exponentially as system sensors and detectable faults are scaled up, which in turn increases the computational power required to run ARMAS in areal-world …