Aerospace Engineering Commons^™

Particle Image Velocimetry Of Transverse Jets In Crossflow, Jesse K. Tsai, Kayla Kuzmich, David Forliti, Kriss Vanderhyde, Nils Sedano

STAR Program Research Presentations

The jet in crossflow (JICF) has been an ongoing study for the past several decades with applications in the field of fluid mechanics. This particular flow field produces vortical structures tied to the entrainment and mixing of two separate fluids. Research of the JICF seeks to determine a model and trajectory scaling law for future designs. This will help future designers to optimize the mixing and homogeneity of the two fluids to decrease emissions from pollutants, make ignition easier, and improve combustion efficiency of rockets.

Our experiment will employ Particle Image Velocimetry (PIV) to determine the fluid motion of the …

Hil Simulation For Smartphone-Guided Autonomous Systems, Matthew Gerdt

Computer Engineering

My bachelor thesis focuses on implementing a Hardware in the Loop (HIL) simulation for a quadcopter controlled by an Android smartphone. The HIL simulation will be able to test the software running on an Android smartphone by simulating a virtual quadcopter on the computer without the need to use an actual quadcopter. To accomplish this I will have to modify my team’s existing simulation to allow for the communication between the smartphone and simulation. At the completion of my work the HIL simulation will allow the testing of different aspects of the Android application, such as the tracking of an …

Effect Of Adaptive Tabs On Drag Of A Square-Base Bluff Body, Brian W. Barker

Master's Theses

This thesis involves the experimental wind tunnel testing of a 0.127m by 0.127m square-base bluff body to test the effectiveness of trailing edge tabulations to reduce drag in the Cal Poly 0.912m by 1.219 m low-speed wind tunnel. To accomplish this, the boundary layer was first measured on the trailing edge of the model for the three speeds at 10, 20, and 30 m/s, with Re = 8.3e4, 1.6e5 and 2.5e5 respectively, without the tabs. Three different tests were performed to determine the effectiveness of the tabs. These tests included base pressure measurements, total drag force measurements and hotwire velocity …

Experimental Investigation Of Active Wingtip Vortex Control Using Synthetic Jet Actuators, Peter J. Sudak

Master's Theses

An experiment was performed in the Cal Poly Mechanical Engineering 2x2 ft wind tunnel to quantify the effect of spanwise synthetic jet actuation (SJA) on the drag of a NACA 0015 semispan wing. The wing, which was designed and manufactured for this experiment, has an aspect ratio of 4.20, a span of 0.427 m (16.813”), and is built around an internal array of piezoelectric actuators, which work in series to create a synthetic jet that emanates from the wingtip in the spanwise direction. Direct lift and drag measurements were taken at a Reynolds Number of 100,000 and 200,000 using a …

Trajectory Optimization For A Misson To The Trojan Asteroids, Shivaji Senapati Gadsing

Masters Theses

The problem of finding a minimum-fuel trajectory for a mission to the Jovian Trojan asteroids is considered. The problem is formulated as a modified traveling salesman problem. Two different types of algorithms such as an exhaustive search algorithm and a serial rendezvous search algorithm are developed. The General Mission Analysis Tool (GMAT) is employed for finding optimum trajectories with minimal fuel consumption. The selection of a minimum-fuel mission trajectory, and the associated target asteroids, will be a key factor in determining feasibility and scientific value of a Trojan tour and rendezvous mission.

The transfer trajectory followed by a spacecraft between …

Mathematical Equations And System Identification Models For A Portable Pneumatic Bladder System Designed To Reduce Human Exposure To Whole Body Shock And Vibration, Ezzat Aziz Ayyad

UNLV Theses, Dissertations, Professional Papers, and Capstones

A mathematical representation is sought to model the behavior of a portable pneumatic foam bladder designed to mitigate the effects of human exposure to shock and whole body random vibration. Fluid Dynamics principles are used to derive the analytic differential equations used for the physical equations Model. Additionally, combination of Wiener and Hammerstein block oriented representation techniques have been selected to create system identification (SID) block oriented models. A number of algorithms have been iterated to obtain numerical solutions for the system of equations which was found to be coupled and non-linear, with no analytic closed form solution. The purpose …

Transonic And Supersonic Ground Effect Aerodynamics, Graham Doig

Aerospace Engineering

A review of recent and historical work in the field of transonic and supersonic ground effect aerodynamics has been conducted, focussing on applied research on wings and aircraft, present and future ground transportation, projectiles, rocket sleds and other related bodies which travel in close ground proximity in the compressible regime. Methods for ground testing are described and evaluated, noting that wind tunnel testing is best performed with a symmetry model in the absence of a moving ground; sled or rail testing is ultimately preferable, though considerably more expensive. Findings are reported on shock-related ground influence on aerodynamic forces and moments …

Feedback Speed Control Of A Small Two-Stroke Internal Combustion Engine That Propels An Unmanned Aerial Vehicle, Paul D. Fjare

UNLV Theses, Dissertations, Professional Papers, and Capstones

Unmanned aerial vehicles (UAV) require intelligent control of their power source. Small UAV are typically powered by electric motors or small two-stroke internal combustion (IC) engines. Small IC engines allow for longer flight times but are more difficult to control and cause significant ground noise. A hybrid operation that uses the engine at high altitudes and the electric motors at low altitudes is desired. This would allow for extended flight with acceptable ground noise levels. Since the engine can not be restarted in the air it must be able to remain at idle for an extended time without stalling. A …

Evaluation And Flight Assessment Of A Scale Glider, Alvydas Anthony Civinskas

Doctoral Dissertations and Master's Theses

The objective of this project is to do a flight assessment of a Phoenix K8B radio controlled glider to see what process is needed to verify its glide slope and stability characteristics. The flight test analysis, plus a computational fluid dynamics analysis, and an industry-like component build-up aerodynamic analysis were done to provide comparable estimates for the aircraft glide slope. A stability and control derivative analysis was also completed and compared using SURFACES, USAF Datcom, and MIT AVL software. The glide slope estimate and stability and control derivatives obtained from flight test data showed considerable range and uncertainty. Potential sources …

Unsteady Viscous Cavity Flow Using Computational Fluid Dynamics, Chandramouli Vadlamudi

Doctoral Dissertations and Master's Theses

The problem of unsteady viscous incompressible flow in a two-dimensional cavity is treated using the unsteady incompressible Navier-Stokes equations with various initial and boundary conditions. First the case of a square cavity with one inlet and one outlet is treated in steady and unsteady flows. The software package ANSYS FLUENT was used in the CFD simulations. This approach captures the appearance of separation bubbles and vortex formation inside the cavity. Steady state flows are also obtained from the unsteady simulations after convergence of the time dependent solutions. Then the case of a cavity with a synthetic jet and two outlets …

Characterization And Testing Of A 5.8 Kv Sic Pin Diode For Electric Space Propulsion Applications, Alexandra Toftul

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Inductive Pulsed Plasma Thrusters (IPPTs) are a type of in-space propulsion that has multiple advantages over conventional chemical propulsion for long-duration, deep space missions. Existing IPPT prototypes utilize spark gap switches, however these are subject to corrosion problems that make them unreliable for long-term use. Recent advances in solid state switching technology have opened up a variety of switching options that could provide greater reliability, controllability, and increased energy efficiency. Taking advantage of this, a novel thruster drive circuit topology containing a high-power silicon controlled rectifier (SCR) and series fast recovery diode (FRD) is proposed that is expected to increase …

Application Of A Modified Backwards Lagrangian Stochastic Model To Estimate Particulate Matter Emissions From A Dairy, Kori Moore, Michael Wojcik, Randy Martin, Richard Pfeiffer, John Prueger, Jerry Hatfield

Space Dynamics Laboratory Publications

Background

• SDL, USU, and ARS have assembled sensors to measure PM and NH₃ concentrations around area sources
• Point and remote sensors, including a PM calibrated scanning lidar
• Emissions estimated using concentration measurements
• Mass balance (lidar only)
• Inverse modeling

Axial Compressor Design With Counter-Rotation And Variable Rpm For Stall Mitigation, Madhur Tiwari

Doctoral Dissertations and Master's Theses

Compressor Stall, an aerodynamic instability due to abnormal air flow in the compressor resulting in loss of total pressure and compressor performance. One of the reasons of compressor stall is due to rise in static back pressure at compressor exit which may result from an imbalance of incidence angle at the rotor and stator and rotational speed. The paper presents the results of a new axial compressor design with counter rotation and variable RPM. Counter-Rotation is used to push compressor performance during stall by moving the operating point away from surge line with a higher pressure ratio rise. Initially an …

Indus University, Amresh Srivastava

Data and Test Instruments

No abstract provided.

Space Layer Experiment (Slx) Sensor Calibration, Scott Hansen, Brian Thompson, Lorin Zollinger, Dean Wada, Ed Hawkins, Brian Kantsiper

Space Dynamics Laboratory Publications

The Space Layer Experiment (SLX) is a sensor planned by the US Missile Defense Agency (MDA) to test technology to observe and track objects in space. Subject to SLX program and funding restraints, a detailed and thorough ground calibration is planned to support observation and tracking goals, with continuing calibration experiments planned after launch. This presentation provides an overview of the SLX ground calibration that will use existing SDL calibration equipment and expertise with allowances made for SLX sensor design and program schedule. Preliminary plans for on-orbit calibration will also be presented with the goal of receiving expert feedback to …

Thermal Resistance At An Interface Between A Crystal And Its Melt, Zhi Liang, William J. Evans, Pawel Keblinski

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Non-Equilibrium Molecular Dynamics Simulations Are Used to Determine Interfacial Thermal Resistance (Kapitza Resistance) between a Crystal and its Melt for Three Materials Including Ar, H2O, and C8H 18 (Octane). the Simulation Results Show that the Kapitza Resistance at a Crystal-Melt Interface is Very Small and Thus Has a Negligible Effect on Thermal Transport Across the Crystal-Melt Interface. the Underlying Origins of This Behavior Are the Very Good Vibrational Property Match between the Two Materials Forming the Interface and Good Interfacial Bonding. the Result Also Indicates that the Commonly-Used Assumption that Temperature Profile is Continuous at the Crystal-Melt Interface is Valid …

Development Of A Real Time Bistatic Radar Receiver Using Signals Of Opportunity, Nicholas Rainville

Open Access Theses

Passive bistatic radar remote sensing offers a novel method of monitoring the Earth's surface by observing reflected signals of opportunity. The Global Positioning System (GPS) has been used as a source of signals for these observations and the scattering properties of GPS signals from rough surfaces are well understood. Recent work has extended GPS signal reflection observations and scattering models to include communications signals such as XM radio signals. However the communication signal reflectometry experiments to date have relied on collecting raw, high data-rate signals which are then post-processed after the end of the experiment. This thesis describes the development …

A Small-Scale Experiment Using Microwave Interferometry To Investigate Detonation And Shock-To-Detonation Transition In Pressed Tatb, Peter John Renslow

Open Access Theses

A small-scale characterization test utilizing microwave interferometry was developed to dynamically measure detonation and run to detonation distance in explosives. The technique was demonstrated by conducting two experimental series on the well-characterized explosive triaminotrinitrobenzene (TATB). In the first experiment series, the detonation velocity was observed at varying porosity. The velocity during TATB detonation matched well with predictions made using CHEETAH and an empirical relation from the Los Alamos National Laboratory (LANL). The microwave interferometer also captured unsteady propagation of the reaction when a low density charge was near the failure diameter. In the second experiment series, Pop-plots were produced using …

Overview Of Instruments For Investigating Dust Interactions On Small Solar System Bodies By Landers And Rovers, Ryan L. Kobrick, Jeffrey A. Hoffman, Kenneth W. Street Jr., Douglas L. Rickman

Publications

Small Solar System bodies such as asteroids, comets and Mars' moons Phobos and Deimos have relatively unknown regolith environments. It is hypothesized that dust preserved in the regolith on the surfaces will have similar mechanical properties to lunar dust because of similar formation processes from micrometeoric bombardment, low relative gravity for slow settling times, and virtually no weathering because there is no atmosphere.

The Study Of Electrostatic And Magnetostatic Active Space Radiation Shielding For Deep Space Missions, Leroy A. Fung

Electrical & Computer Engineering Theses & Dissertations

A goal of the National Aeronautics and Space Administration (NASA) has been to develop technologies that will enable deep space explorations. Such missions include a prolonged stay on the Moon and the ability to sustain a long duration of travel time to Mars and beyond. Long-term human exposures to radiation are a crucial concern. Recent research has taken focus on active and passive shielding methods as a way of eliminating the hazard posed by radiation particles. Passive shielding involves the use of materials that has the ability to withstand radiation particles and reduce the dose by stopping or slowing the …