Aerodynamics and Fluid Mechanics Commons^™

Inlet Shape Considerations For Split-Wing Electric Distributed Propulsion, Kurt Vonderhaar Papathakis

Master's Theses

This thesis aims to uncover preliminary design relationships for an inlet of a split-wing electric distributed propulsion regional airliner. Several aspects of the inlet design were investigated, including: the overall thickness of the airfoil section with respect to the chord, inlet throat area, and lip radius. These parameters were investigated using several angles of attack and mass flow rates through the fan. Computational fluid dynamics, with a 2^nd Order turbulence model was used and validated against World War II era data from NACA, as those studies were the most pertinent wind tunnel data available. Additionally, other works by Boeing, …

A Contribution Toward Better Understanding Of Overbanking Tendency In Fixed-Wing Aircraft, Nihad E. Daidzic

Journal of Aviation Technology and Engineering

The phenomenon of overbanking tendency for a rigid-body, fixed-wing aircraft is investigated. Overbanking tendency is defined as a spontaneous, unbalanced rolling moment that keeps increasing an airplane’s bank angle in steep turns and must be arrested by opposite aileron action. As stated by the Federal Aviation Administration, the overbanking tendency may lead to a loss of control, especially in instrument meteorological conditions. It was found in this study that the speed differential over wing halves in horizontal turns indeed creates a rolling moment that achieves maximum values for bank angles between 45 and 55 degrees. However, this induced rolling moment …

Magnus Effect In Duct Flow, Jesse S. Batko, Cameron W. Clarke, Kenneth W. Smith Jr.

Williams Honors College, Honors Research Projects

The following research paper details the preliminary research carried out by this team. The project was originally conceived to determine if Magnus Lift could be utilized in an unconventional way to assist rockets during takeoff. Several conceptual designs were proposed, but the idea was scrapped when it became apparent that the team would not be able to generate the desired lift without inducing significant amounts of drag and additional weight on a rocket. Instead, the team focused on researching an interesting topic that hasn’t been previously explored: Magnus lift on a cylinder within a duct.

An experimental procedure that could …

Magnus Effect In Duct Flow, Cameron W. Clarke, Jesse S. Batko, Kenneth W. Smith Jr.

Williams Honors College, Honors Research Projects

The following research paper details the preliminary research carried out by this team. The project was originally conceived to determine if Magnus Lift could be utilized in an unconventional way to assist rockets during takeoff. Several conceptual designs were proposed, but the idea was scrapped when it became apparent that the team would not be able to generate the desired lift without inducing significant amounts of drag and additional weight on a rocket. Instead, the team focused on researching an interesting topic that hasn’t been previously explored: Magnus lift on a cylinder within a duct. An experimental procedure that could …

Use Of Single Stage Model Rockets To Teach Some Engineering Principles And Practices To First Year Engineering And Engineering Technology Students, Hüseyin Sarper, Linda Vahala

Electrical & Computer Engineering Faculty Publications

Model rocketry has been called miniature astronautics; a technology in miniature, a hobby, a sport, a technological recreation, an educational tool, and it is all of these things. This paper will describe student projects using model rockets and engines to learn engineering principles for launching rockets and determining the apogee. Model rocketry is a powerful tool for instructors who wish to incorporate science, technology, engineering, and mathematics into a fun, engaging, and challenging activity for first year engineering students. The apogee can be determined using four distinct methods: trigonometry using hand held angle measuring tools, onboard altimeter devices, analytical calculations …

Achieving Global Range In Future Subsonic And Supersonic Airplanes, Nihad E. Daidzic Ph.D., Sc.D.

International Journal of Aviation, Aeronautics, and Aerospace

No commercial airplane in service today is able to fly half great-circle distances over the globe and achieve the non-stop or the global range to any antipodal location on Earth. A subsonic jetliner has the optimum cruising speed at Mach numbers approaching the drag divergence Mach number while still preserving relatively high aerodynamic efficiency. Various fuel-flow laws were used to investigate the cruise performance of subsonic and supersonic aircraft. The effect of wind and aircraft weight and how it affects the optimal cruising airspeed was investigated. Of all different operational cruising techniques, the cruise-climb at high Mach numbers is the …

Laminar Deflagrated Flame Interaction With A Fluidic Jet Flow For Deflagration-To-Detonation Flame Acceleration, Joseph P. Mcgarry

Mechanical & Aerospace Engineering Theses & Dissertations

The concept of the Pulse Detonation Engine (PDE) has been of interest for centuries. The issue was originally studied to understand flame propagation in mine shafts after explosions due to methane buildup. The flames would travel down the shafts, transitioning to turbulent flames due to the roughness of the shaft walls, and accelerate to detonation, delivering powerful, destructive forces. The potential for efficient energy production was noticed, and the theory behind flame propagation was later applied to developing propulsion systems. Recently, researchers have begun to understand the full potential of PDEs to efficiently produce an immense amount of thrust due …

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 …

Gust Mitigation Of Micro Air Vehicles Using Passive Articulated Wings, Adetunji Oduyela, Nathan Slegers

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Birds and insects naturally use passive flexing of their wings to augment their stability in uncertain aerodynamic environments. In a similar manner, micro air vehicle designers have been investigating using wing articulation to take advantage of this phenomenon. The result is a class of articulated micro air vehicles where artificial passive joints are designed into the lifting surfaces. In order to analyze how passive articulation affects performance of micro air vehicles in gusty environments, an efficient 8 degree-of-freedom model is developed. Experimental validation of the proposed mathematical model was accomplished using flight test data of an articulated micro air vehicle …

Adaptive Control Techniques For Transition-To-Hover Flight Of Fixed-Wing Uavs, Brian Decimo Marchini

Master's Theses

Fixed-wing unmanned aerial vehicles (UAVs) with the ability to hover combine the speed and endurance of traditional fixed-wing fight with the stable hovering and vertical takeoff and landing (VTOL) capabilities of helicopters and quadrotors. This combination of abilities can provide strategic advantages for UAV operators, especially when operating in urban environments where the airspace may be crowded with obstacles. Traditionally, fixed-wing UAVs with hovering capabilities had to be custom designed for specific payloads and missions, often requiring custom autopilots and unconventional airframe configurations. With recent government spending cuts, UAV operators like the military and law enforcement agencies have been urging …

Design Advantages Of Skin Friction Drag Reduction Using Riblets, John Michael Gregory

Mechanical & Aerospace Engineering Theses & Dissertations

The research reported here has examined the potential improvements in overall aircraft performance that can result from integrating skin friction reduction technology, such as riblets, early in the aircraft design cycle. This study has shown that riblets can improve the payload capacity, increase the range, and improve performance of transport aircraft. If recent advances in fabrication techniques make it possible to create aluminum wing surfaces with integral riblet geometries, the applications could be widespread and the gains significant.

Active-Twist Rotor Blades Design, Analysis, And Testing, Andrew Randall Kreshock

Mechanical & Aerospace Engineering Theses & Dissertations

The subject of this thesis is the design, analysis, and experimental assessment of active-twist rotors. These active rotors use piezoelectric actuators embedded in the skins to twist the blade to reduce vibratory loads in the fixed system. First, the design and optimization of the twist response within the geometric and structural constraints of a rotor blade is presented. A parametric analysis is conducted varying the airfoil thickness, active-material placement, and structural plies to determine the maximum static twist response. A Macro-Fiber Composite (MFC), which is a fibrous piezoelectric device is used as the active material. Analyses of the cross-section are …

Ramjet Combustion Chamber, Paul Cameron Stone

Aerospace Engineering

A ramjet combustion chamber is designed and some initial assembly fabrication and test completed as a component of a ramjet graduate project for California Polytechnic State University, San Luis Obispo Supersonic Wind Tunnel. The combustor design is driven by a theoretical model created by a Cal Poly graduate student, Harrison Sykes. Temperature, pressure, and fuel flow will be measured.

Nonlinearity Index Analysis Of Periodic-Chaotic Stall-Spin Aircraft Motion, Daniel Paul Tapolcai

Mechanical & Aerospace Engineering Theses & Dissertations

This thesis explores the application of nonlinearity index theory to the nature of stalling and spinning aircraft motions. Nonlinear dynamic phenomena related to stall and spin have been a concern to flight engineers and pilots for generations. Considerable past work has been directed to detect and understand the cause and nature of these phenomena. Methods such as bifurcation analysis, Volterra expansion series, and nonlinear simulation are a few of the nonlinear approaches developed to study this topic. Traditionally, however, linear analysis is the most widely used approach for studying aircraft dynamical behavior under a given set of acceptable conditions. This …

Design And Performance Of Circulation Control Geometries, Rory Martin Golden

Master's Theses

With the pursuit of more advanced and environmentally-friendly technologies of today’s society, the airline industry has been pushed further to investigate solutions that will reduce airport noise and congestion, cut down on emissions, and improve the overall performance of aircraft. These items directly influence airport size (runway length), flight patterns in the community surrounding the airport, cruise speed, and many other aircraft design considerations which are setting the requirements for next generation aircraft. Leading the research in this movement is NASA, which has set specific goals for the next generation regional airliners and has categorized the designs that meet the …

High Performance Modeling Of Atmospheric Re-Entry Vehicles, Alexandre Martin, Leonardo C. Scalabrin, Iain D. Boyd

Mechanical Engineering Faculty Publications

Re-entry vehicles designed for space exploration are usually equipped with thermal protection systems made of ablative material. In order to properly model and predict the aerothermal environment of the vehicle, it is imperative to account for the gases produced by ablation processes. In the case of charring ablators, where an inner resin is pyrolyzed at a relatively low temperature, the composition of the gas expelled into the boundary layer is complex and may lead to thermal chemical reactions that cannot be captured with simple flow chemistry models. In order to obtain better predictions, an appropriate gas flow chemistry model needs …

Modeling Of Heat Transfer Attenuation By Ablative Gases During The Stardust Re-Entry, Alexandre Martin, Iain D. Boyd

Mechanical Engineering Faculty Publications

The great majority of modern space vehicles designed for planetary exploration use ablative materials to protect the payload against the high heating environment experienced during re-entry. In order to properly model and predict the aerothermal environment of the vehicle, it is imperative to account for the gases produced by ablation processes. In the case of charring ablators, where an inner resin is pyrolyzed at a relatively low temperature, the composition of the gas expelled into the boundary layer is complex and may lead to thermal chemical reactions that cannot be captured with simple flow chemistry models. In order to obtain …

Aerodynamics And Control Of A Deployable Wing Uav For Autonomous Flight, Michael Thamann

Theses and Dissertations--Mechanical and Aerospace Engineering

UAV development and usage has increased dramatically in the last 15 years. In this time frame the potential has been realized for deployable UAVs to the extent that a new class of UAV was defined for these systems. Inflatable wing UAVs provide a unique solution for deployable UAVs because they are highly packable (some collapsing to 5-10% of their deployed volume) and have the potential for the incorporation of wing shaping. In this thesis, aerodynamic coefficients and aileron effectiveness were derived from the equations of motion of aircraft as necessary parameters for autonomous flight. A wind tunnel experiment was performed …

Boundary Layer Measurements Related To Wind Tunnel Testing Of Riblets, Emrah Cinar

Mechanical & Aerospace Engineering Theses & Dissertations

With fuel economy being a significant factor in today's world of aviation, aircraft manufacturers have been looking into ways to decrease drag to save fuel. Drag reduction using riblets on wing and fuselage surfaces is . an area that has been studied extensively for the last two decades. In preparation for a larger project which will use several methods to simulate this phenomena, small scale research had to be done to find ways to generate similar conditions on scaled models in a low speed wind tunnel and examine boundary layer behavior.

In this project, boundary layer measurement techniques, such as …

Design, Manufacturing And Testing Of An Environmentally-Green Bipropellant Thruster, Alex Bendoyro, Gabriel Sanchez, Erin Stearns, Phillip Takahashi

Aerospace Engineering

This project reviews the design, manufacturing and experimentation process of a green bi-propellant thruster designed to output 5 lbf. The goals were to successfully design, manufacture and test a thruster, while discovering the complications that arise through out the complete design process of a green thruster. The thruster was successfully designed using ideal rocket equations and the design was successfully confirmed using CFD and FEA. Manufacturing of the thruster was fully planned and revealed mild flaws in thruster design. For example some features were not manufacturable to the exact measurements desired. Testing of the engine gave results inconsistent with expected …

Designing The Human-Powered Helicopter: A New Perspective, Gregory Hamilton Gradwell

Master's Theses

The concept of human-powered vertical flight was studied in great depth. Through the manipulation of preexisting theory and analytical methods, a collection of design tools was created to expediently conceptualize and then analyze virtually any rotor. The tools were then arranged as part of a complete helicopter rotor design process. The lessons learned as a result of studying this process—and the tools of which it consists—are presented in the following discussion. It is the belief of the author that by utilizing these tools, as well as the suggestions that accompany them, future engineers may someday build a human-powered helicopter capable …

Airplane Landing Flare-The Last 5 Seconds, Nihad E. Daidzic

Aviation Department Publications

No abstract provided.

Multidisciplinary Design Optimization Of Transonic Airfoil Sections Using Multiobjective Optimization And Computational Intelligence Tools, Amit A. Kulkarni

Mechanical & Aerospace Engineering Theses & Dissertations

The design of transonic airfoils for civil aviation applications has been a major engineering challenge in the last fifty years. This design problem arises due to the need to limit shock wave drag at a given transonic speed. In recent years, the requirement to reduce the levels of aircraft noise has started to affect the airfoil design process. The multidisciplinary aerodynamic shape optimization problem is treated in this thesis using a multi-objective approach. The objectives correspond to the design of transonic airfoil sections with low drag during cruise and low trailing edge noise levels during the approach condition. The optimization …

Cal Poly Flight Test Platform For Instrument Development, Kyle Schaller, Ian Muceus, Aaron Ells

Aerospace Engineering

This report summarizes a six month effort to conceptually design, develop, and build an unmanned aerial vehicle to test a boundary layer data system (BLDS) developed by Dr. Russell Westphal and his team of mechanical engineering senior design students. The project is funded by Edwards Air Force Base and the United States Air Force Research Laboratory. During the first Cal Poly quarter of project work, January 4, 2010 to March 18, 2010, the team completed a conceptual and preliminary design. During the second quarter, March 18, 2010 to June 12, 2010, the team completed the construction and initial flight test …

Analysis Of Curvature Effects On Boundary Layer Separation And Turbulence Model Accuracy For Circulation Control Applications, Daniel Wilde

Aerospace Engineering

This set of analyses involves flow separation in high curvature regions with special attention to circulation control implementations. Blown flaps of various shapes designed by Rory Golden for use on the AMELIA, or Advanced Model for Extreme Lift and Improved Aeroacoustics, short takeoff vehicle have exhibited flow separation at locations where flap curvature changes. Investigating this problem, its causes, and potential solutions, I have concluded that the separation is equally a function of the flow simulation turbulence model used, and the geometry of the flap itself. Using Gambit version 11.0.1 for grid generation and Fluent version 6.3.26 for CFD calculations, …

Blended Wing Body Form Factor Code And Model Center Integration, Simone (Simo) Alberti

Aerospace Engineering

This senior project investigated a method of calculating the form factor of an arbitrarily shaped wing, such as a blended wing body, from its pressure coefficient distribution. A Matlab script was coded and integrated into an existing Model Center tool for blended wing bodies. Model Center allows a VSP model to be analyzed with PMARC, a panel code, to determine the pressure distribution over a wing. The Matlab code can then calculate the form factor and critical Mach number. It was found that the code can accurately model simple planar wings, validated against empirical equations, and is robust for blended …

Numerical Examination Of Flow Field Characteristics And Fabri Choking Of 2d Supersonic Ejectors, Brett G. Morham

Master's Theses

An automated computer simulation of the two-dimensional planar Cal Poly Supersonic Ejector test rig is developed. The purpose of the simulation is to identify the operating conditions which produce the saturated, Fabri choke and Fabri block aerodynamic flow patterns. The effect of primary to secondary stagnation pressure ratio on the efficiency of the ejector operation is measured using the entrainment ratio which is the secondary to primary mass flow ratio.

The primary flow of the ejector is supersonic and the secondary (entrained) stream enters the ejector at various velocities at or below Mach 1. The primary and secondary streams are …

Multi-Element Airfoil Optimization Using Computational Fluid Dynamics, Mustafa Kubilay Ictuzer

Mechanical & Aerospace Engineering Theses & Dissertations

High-lift systems are frequently used on commercial transport aircrafts to obtain low speed performance, in terms of take-off and landing field lengths and approach speed. To maximize the take-off and landing performance within the critical restrictions required by the new generation transport wing designs, enhanced high-lift technologies are needed. Moreover, the economic realities faced by the airlines require a design that is mechanically simple and effective. These facts lead us to the optimization of the high lift systems.

Optimizing a high-lift system improves an aircraft's take-off and landing performance. The weight of the system, the advantages and the disadvantages all …

A Structural Dynamic Analysis Of A Manduca Sexta Forewing, Travis W. Sims

Theses and Dissertations

Micro air vehicles (MAVs) are intended for future intelligence, surveillance, and reconnaissance use. To adequately fulfill a clandestine capacity, MAVs must operate in close proximity to their intended target without eliciting counter-observation. This objective, along with DARPA’s constraint of a sub-15 centimeter span, requires future MAVs to mimic insect appearance and flight characteristics. This thesis describes an experimental method for conducting a structural analysis of a Manduca Sexta (hawkmoth) forewing. Geometry is captured via computed tomography (CT), and frequency data is collected using laser vibrometry in air and vacuum. A finite element (FE) model is constructed using quadratic beams and …

Dive Angle Sensitivity Analysis For Flight Test Safety And Efficiency, Matthew T. Schneider

Theses and Dissertations

Flutter envelope expansion is one of the most critical types of developmental flight tests. The regions that present the most dangerous flight profiles are those test points in the negative PS realm of the flight envelope. These points develop into high-speed dives and require an accurate predictive model to prevent possible testing accidents. As a flight test is conducted, several conditions such as aircraft weight and ambient air temperature can change, causing a drastic shift in the excess power profiles resulting in significant alteration in the test conditions. Using a dive planning model, a number of parameters were analyzed to …