Aerospace Engineering Commons^™

Entrainment Processes For A Jet In Cross-Flow: The Quantification Of Turbulent Contributions And Their Importance On Accurate Modeling, Graham Asher Freedland

Dissertations and Theses

A jet in cross flow (JICF) is examined experimentally by injecting a stream of air into crossing fluid with an aim into quantifying entrainment process and downstream evolution. The behavior of JICF is important to fields ranging from turbine-blade cooling to smokestack pollution and volcanic eruption dynamics. Existing simplified volcanic plume models are tested; most importantly, the near-field contributions of complex interconnected vortex systems, which present significant uncertainties because they assume negligible turbulence. While jets in irrotational cross-flow have been investigated, this analysis has focused on the interaction between a turbulent jet in low and highly turbulent cross-flow created by …

Very Light Jet Trainer (Vlj) - Phoenix Iv, Saxton Robinson, Eric Gentry, Daniyel Holmes, Navee Cheng

Senior Design Project For Engineers

This project was pursued to bring another possible solution to a major problem within the pilot training industry. When it comes to pilots training with aircraft, they must often use repurposed older aircraft to log their training hours. With few options when it comes to aircraft that are designed specifically for training, we have researched, modeled, and simulated tests for our own trainer jet to add to the market. The aircraft was designed to seat 4-8 people (1-2 for crew and 2-6 for passengers), weigh less than 10,000 lbs., have a range of about 1195.5 nautical miles, have a max …

The Varied Thermal Response Of Magnetic Iron-Oxide Nanoparticles During Induction Heating In Liquid And Solid-Liquid Phase Change Mediums, Joshua Tompkins

Graduate Theses and Dissertations

This study investigates the induction heating response of uncapped iron oxide nanoparticles sonically dispersed as a nanofluid and mechanically distributed in solid phase change materials. The nanoparticles examined have a mean diameter of 14.42 nm and are magnetically heated in an alternating magnetic field at an amplitude of 72.6 kA/m at frequencies of 217, 303, and 397 kHz. Nanoparticle characterization was undertaken through transition electron microscopy, x-ray diffraction, and dynamic light scattering when in suspension. Carrier fluids were characterized through viscosity, heat capacity, and density measurements which were used in the calorimetric calculation of the specific absorption rate (SAR) of …

Nanoscale Mechanics Of Disordered Biomolecules In Brain, Md Ishak Khan

Mechanical and Aerospace Engineering Dissertations - Archive

The long-term objective of this dissertation is to link blast-induced traumatic brain injury (TBI) with multiscale, multiphysics damage evolution in the brain using experimentally verifiable computations and simulations. The short-term goal is to conduct modeling and simulation to correlate dynamic mechanical loading to damage in sub-axonal components. It is known that the interior of the brain at the macroscale (10^-1 m) is composed of two distinct components, the grey matter, and the white matter. Within the cortex, the grey matter primarily takes the form of cortical columns (mesoscale: 10^-3 m), which are six layered structures, each composed of 8-10 thousand …

Analytical And Experimental Studies On Mixing In Supersonic Flows, Vijay Gopal

Mechanical and Aerospace Engineering Dissertations - Archive

Mixing enhancement in supersonic flow is an important domain of research for enabling the realization of efficient and scalable high speed air-breathing engines (scramjet). Introducing streamwise vorticies in supersonic flow and tailoring their interactions for mixing enhancement is the primary motivation for the present research study. Leveraging the research performed in the group at the Aerodynamics Research Center (ARC), systematic experimental studies on mixing enhancement is carried out in supersonic flows by tailoring the selected modes of streamwise vortex interactions with the aid of in-house developed reduced order method VorTX. This method utilizes the lifting line-vortex theory in supersonic flow …

Automating Aerospace Synthesis Code Generation A Tool For Generic Vehicle Design And Technology Forecasting, Thomas Peter Mccall

Mechanical and Aerospace Engineering Dissertations - Archive

The principal development and deliverable of this research is a generic synthesis assembling decision support environment for early conceptual design that automates the assembly of synthesis architectures for enhanced product exploration and technology forecasting. The objective of this research is to develop a baseline environment to assess complex vehicle automated synthesis architecture synthetization procedures for adaptation into a greater cognitive system. This tool has been developed as a precursory and developmental task in an initiative towards an artificial intelligence design and research assistant peer. The artificial intelligence peer is a perceived course for future design system evolution in the continued …

Using Numerical Modeling To Determine Viscous Losses Within Helium Turbomachinery, Benjamin Uhlig

Mechanical and Aerospace Engineering Theses - Archive

As the consumption of energy has increased relentlessly over the last few decades, the need for reliable clean energy generation has increased as well. Currently, nuclear power is the only method capable of providing a stable supply of clean energy, although the nuclear energy generation process still requires improvement. Specifically, there is a need to increase efficiencies while reducing the risks of radioactive contamination. It is possible that both these issues may be mitigated using helium as the working fluid. However, the performance of turbomachinery using helium must be evaluated before its use can be implemented. To do this, Balaji …

Determination Of Landing Zones Of Quadrotors Experiencing In-Flight Failures, Ahmet Tolcu

Mechanical and Aerospace Engineering Theses - Archive

In recent years, unmanned aerial vehicles (UAVs), commonly known as drones, have attained considerable prominence in a wide range of areas ranging from military operations, including surveillance, intelligence, and reconnaissance, to nonmilitary sectors such as delivery, entertainment, and agriculture. The low cost, small size, and ease of use of quadrotors provide significant advantages for such missions. At the same time however, the occurrence of physical failures in such vehicles, particularly if these failures occur while flying over highly populated areas, can pose considerable risk to people and premises on the ground. This thesis investigates scenarios of power loss due to …

Experimental Assessment Of Rack-Level Dynamic Direct To Chip Liquid Cooling For Data Center And It Equipment Reliability, Amith Mathew

Mechanical and Aerospace Engineering Theses - Archive

Data centers are used by organizations for storing, processing and distribution of data. These data centers are run through-out the year due to which their thermal management is a growing concern. A popular way of eliminating such thermal cooling issues is Liquid cooling. Conventionally Liquid cooling involves the supply of constant liquid flow (water or refrigerant) through the IT rack irrespective of the IT load, which in a Multi-chip module causes hotspots and temperature gradients across the module due to non-uniform heating. A dynamic cold-plate and a regulatory flow control device (FCD) is incorporated in this experimental set-up to assist …

Modular Framework For Implementation And Analysis Of Recursive Filters With Considered And Neglected Parameters, Kyle J. Demars, Kari C. Ward

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper develops novel covariance and square-root factor formulations of a consider-neglect Kalman filter for navigation applications. The proposed filter partitions system parameters into three distinct categories: those to be estimated by the filter, those whose contribution to the system are considered without being explicitly estimated, and those with sufficiently low effect on the system such that their contribution can be neglected altogether. Discussion on appropriate selection of parameters to be considered and neglected is provided with specific attention given to descent-to-landing navigation. Monte Carlo simulations and analysis are performed to assess the performance of the developed square-root consider-neglect filter …

Laser-Based Interfacial Patterning Enables Toughening Of Cfrp/Epoxy Joints Through Bridging Of Adhesive Ligaments, Ran Tao, Xiaole Li, Arief Yudhanto, Marco Alfano, Gilles Lubineau

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The ability to prevent catastrophic failures in secondary bonded CFRP adhesive joints is important for reliable automotive and aerospace structures. In a previous study, we proposed an innovative damage-tolerant interfacial design concept for adhesively bonded composite joints, which relied on the extrinsic dissipation of bridging adhesive ligaments enabled by controlling the adhesion at CFRP/epoxy interfaces. In this work, we experimentally validate this strategy by combining laser processing and mechanical testing using double cantilever beam (DCB) joints. Mechanical tests indicate that the pattern geometry, i.e., number and spacing of the areas with different adhesion, controls the formation of either single or …

Investigation On The Use Of Small Aperture Telescopes For Leo Satellite Orbit Determination, Luis R. Curiel Iii

Master's Theses

The following thesis regards the use of small aperture telescopes for space domain awareness efforts. The rapidly populating space domain was motivation for the development of a new operation scheme to conduct space domain awareness feasibility studies using small telescopes. Two 14-inch Schmidt-Cassegrain Telescopes at the California Polytechnic State University and the Air Force Research Lab in Kirtland AFB, NM, in conjunction with a dedicated CCD camera and a commercial DSLR camera, were utilized to conduct optical observations on satellites in Earth orbit.

Satellites were imaged during August 2019, and from January 2020 to March 2020, resulting in the collection …

Field Testing The Effects Of Low Reynolds Number On The Power Performance Of The Cal Poly Wind Power Research Center Small Wind Turbine, John B. Cunningham

Master's Theses

This thesis report investigates the effects of low Reynolds number on the power performance of a 3.74 m diameter horizontal axis wind turbine. The small wind turbine was field tested at the Cal Poly Wind Power Research Center to acquire its coefficient of performance, C­_p, vs. tip speed ratio, λ, characteristics. A description of both the wind turbine and test setup are provided. Data filtration and processing techniques were developed to ensure a valid method to analyze and characterize wind power measurements taken in a highly variable environment. The test results demonstrated a significant drop in the …

Design And Validation Of An Led-Based Solar Simulator For Solar Cell And Thermal Testing, Matthew Gunther

Master's Theses

An LED-based solar simulator has been designed, constructed, and qualified under ASTM standards for use in the Cal Poly Space Environments Laboratory. The availability of this simulator will enhance the capability of undergraduate students to evaluate solar cell and thermal coating performance, and offers further research opportunities. The requirements of ASTM E927-19 for solar simulators intended for photovoltaic cell testing were used primarily, supplemented by information from ASTM E491-73 for solar simulators intended for spacecraft thermal vacuum testing. Three main criteria were identified as design goals - spectral match ratio, spatial non-uniformity, and temporal instability. An electrical design for an …

Analysis Of Glass Transition Temperature Of Pcb & Substrate Using Dynamic Mechanical Analysis & Thermomechanical Analysis, Shristi Yadav

Mechanical and Aerospace Engineering Theses - Archive

Electronic Packaging materials and their properties examines the array of packaging architecture, outlining the classification of materials and their use for various tasks requiring performance over time. Glass transition temperature plays a vital role in the field of Electronic Packaging. It is the temperature range where the material changes from a rigid glassy material to a soft (not melted) material and is usually measured in terms of the stiffness or modulus. The commonly used component in today’s electronics world are PCBs and substrate which are an integral part of it. There are few known ways of finding out the Glass …

Analysis Of After Impact Characteristics And Structural Optimization Of Cfrp Composite Plate, Zhennan He

Doctoral Dissertations and Master's Theses

Low-velocity impact (LVI) on composites may cause Barely Visible Impact Damage (BVID), which is one of the most common damage types and may result in a decrease in strength of the composite. The objectives of this research were (a) to identify the characteristics of a carbon/epoxy composite plate after low-velocity impact, (b) to create a validated model to simulate the impact process and progressive failure, and (c) to perform sizing and shape optimization of the laminate for improving the damage resistance of the plate. As a part of this thesis, composite plates were fabricated using carbon fiber reinforced polymer (CFRP) …

Foundations Of The Geometric Mechanics Udwadia-Kalaba Framework For Rigid Body Constrained Motion Analysis, Brennan S. Mccann

Doctoral Dissertations and Master's Theses

Presented herein are multiple tools for constrained motion analysis extended to different dynamical frameworks. The Udwadia-Kalaba (UK) formalism for the constrained motion analysis of a point mass is a well-documented and applied methodology. Here, UK formulation is generalized to the dynamics of rigid bodies on nonlinear manifolds in the geometric mechanics framework. This approach simultaneously treats rotational and translational motion in a unified method without encountering singularites or non-uniqueness, issues that would arise were attitude parameterization sets used. The viability of this geometric mechanics UK formalism is demonstrated for the cases of fully and underconstrained systems. The nominal UK formalism …

Relative Attitude Dynamics And Control Of Spacecraft Using Electrostatic Torque, John Galjanic

Doctoral Dissertations and Master's Theses

Recent years have seen an increased interest in spacecraft formation flying, with many applications requiring that the members of these formations maintain specific relative attitude configurations. One low-cost method that has been considered to accomplish this is the use of electrostatic torques, which are generated by charging the surfaces of involved spacecraft to allow interaction without physical contact. The research presented in this thesis analyzes a pair of cylindrical-bodied spacecraft operating in deep space. Specifically, the suitability of using electrostatic torques as an actuator to synchronize the two spacecraft's attitude responses is under consideration. The study considers a simplified case, …

Flexible Strain Detection Using Surface Acoustic Waves: Fabrication And Tests, Rishikesh Srinivasaraghavan Govindarajan

Doctoral Dissertations and Master's Theses

Over the last couple of decades, smart transducers based on piezoelectric materials have been used as sensors in a wide range of structural health monitoring applications. Among them, a Surface Acoustic Wave sensor (SAW) offers an overwhelming advantage over other commercial sensing technologies due to its passive, small size, fast response time, cost-effectiveness, and wireless capabilities. Development of SAW sensors allows investigation of their potential not only for measuring less-time dependent parameters, such as pressure and temperature, but also dynamic parameters like mechanical strains. The objective of this study is to develop a passive flexible SAW sensor with optimized piezoelectric …

Parametric Analysis Of Particle Spreading With Discrete Element Method, Yuxuan Wu

Doctoral Dissertations and Master's Theses

The spreading of metallic powder on the printing platform is vital in most additive manufacturing methods, including direct laser sintering. Several processing parameters such as particle size, inter-particle friction, blade speed, and blade gap size affect the spreading process and, therefore, the final product quality. The objective of this study is to parametrically analyze the particle flow behavior and the effect of the aforementioned parameters on the spreading process using the discrete element method (DEM). To effectively address the vast parameter space within computational constraints, novel parameter sweep algorithms based on low discrepancy sequence (LDS) are utilized in conjunction with …