Aerodynamics and Fluid Mechanics Commons^™

Formula Sae Preliminary Aerodynamic Design, Robert Coates, Matt Wright

Von Braun Symposium Student Posters

No abstract provided.

Analytic Treatment Of Vortex States In Cylindrical Superconductors In Applied Axial Magnetic Field, Andrei Ludu, J. Van Deun, M. V, Milosevic, A. Cuyt, F. M. Peeters

Publications

We solve the linear Ginzburg–Landau GL equation in the presence of a uniform magnetic field with cylindrical symmetry and we find analytic expressions for the eigenfunctions in terms of the confluent hypergeometric functions. The discrete spectrum results from an implicit equation associated to the boundary conditions and it is resolved in analytic form using the continued fractions formalism. We study the dependence of the spectrum and the eigenfunctions on the sample size and the surface conditions for solid and hollow cylindrical superconductors. Finally, the solutions of the nonlinear GL formalism are constructed as expansions in the linear GL eigenfunction basis …

Development Of Measurement Methods For Application To A Wind Tunnel Test Of An Advanced Transport Model, Robert S. Ehrmann

Master's Theses

California Polytechnic State University, San Luis Obispo is currently working towards developing a Computational Fluid Dynamics (CFD) database for future code validation efforts. Cal Poly will complete a wind tunnel test on the Advanced Model for Extreme Lift and Improved Aeroacoustics (AMELIA) in the National Full-Scale Aerodynamics Complex (NFAC) 40 foot by 80 foot wind tunnel at NASA Ames Research Center in the summer of 2011. The development of two measurement techniques is discussed in this work, both with the objective of making measurements on AMELIA for CFD validation.

First, the work on the application of the Fringe-Imaging Skin Friction …

Implementation Of A Conrad Probe On A Boundary Layer Measurement System, Charles Rocky Ulk

Master's Theses

This thesis presents the design, calibration, and performance evaluation of a type of two-hole pressure probe anemometer known as a Conrad probe, as well as its subsequent implementation on an autonomous, compact boundary layer measurement device and its first application for subsonic in-flight measurements of a swept wing boundary layer. Calibration of the Conrad probe was accomplished using two calibration functions and a non-nulling method for resolving in-plane flow velocity direction and magnitude over a range of ±30 degrees. This approach to calibration and application offered the advantages of rapid data acquisition with lower energy consumption than alternative methods for …

Extension To Multiple Species Of A Two-Equation Turbulence Model For High Speed Flows, Martin Horvath

Master's Theses - Daytona Beach

The Wilcox (2006) k-co turbulence model has been extended to multiple species and implemented in a CFD code for high speed flows using the Steger-Warming flux-vector splitting scheme. The model was chosen because compressibility corrections are not required, nor are viscous damping factors or wall functions to produce the law of the wall, and it has previously been validated for approximately one hundred test cases ranging from incompressible to hypersonic flow regimes. Initial validation cases using first-order accuracy have been performed, including a Mach 2.5 flow past a backward-facing step and a Mach 2.85 flow into a 24° compression corner. …

Analysis Of A Passive Flow Control Device Via Flow Visualization Techniques, Cheryl R. Graham, Shi (Peter) Huang

Aerospace Engineering

This report details an experiment done to verify the effectiveness of a passive flow control system on a two-dimensional bluff body, blunt trailing edge model in controlling wake dimension and Karman vortex sheds. An earlier experiment by Park, et.al.[1] performed analysis via wind tunnel pressure testing and computerized model to determine the ideal proportions of such a tab design and identify the flow properties responsible for the potential drag reduction. To obtain visual verification of the existence of these concepts, a bluff body model proportionally identical to the one used by Park, et.al., was designed and tested in a water …

Alterations Of The Cal Poly Supersonic Wind Tunnel To Increase Accuracy And Prove The Absence Of Shockwaves, Garrett A. Lovell, Hector A. Gonzalez

Aerospace Engineering

The calibration and improvement of the Cal Poly supersonic wind tunnel was performed in order to create a fully functional facility for supersonic testing. While investigating possible shocks present in the wind tunnel, it was discovered that the real concern was not the tunnel but the measurement systems. Both measurement systems, pitot tube and Schlieren, were evaluated and were found to be deficient. The pitot system had so much play in it that it bent backward every time the tunnel was run invalidating the results, and giving false shock data. The Schlieren system was missing one vital component to make …

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, …

Hybrid Rocket Motor, Zach Arena, Alexander Athougies, Alden Rodulfo

Aerospace Engineering

This project involves the re-design, manufacturing, and testing of the Cal Poly Space System’s 4th iteration of an M-class 98mm hybrid rocket motor. This motor utilizes hydroxyl-terminated polybutadiene as fuel with liquid nitrous oxide as the oxidizer. Modeling and analysis was conducted on a 12 port self-impinging swirl injector and fuel manufacturing to improve performance. Several hot and cold flow tests were conducted to validate the analysis and predict performance values. Test results included two test fires resulting in an average of 212 lbf of thrust for 6 seconds with an Isp of 160 seconds and an average thrust of …

Conceptual Aircraft Hinge Moment Measurement System, Erin M. Hambrick, Nicole M. Thomason

Aerospace Engineering

The Conceptual Aircraft Hinge Moment Measurement System (CAHMMS) was designed, prototyped, and validated to improve hinge moment estimates early in the design process. Validation was performed by integrating CAHMMS with a test wing and conducting wind tunnel tests to compare the expected theoretical, historical, and Computational Fluid Dynamics (CFD) predictions to the experimental results. As CAHMMS is an external measurement system, interference effects at the connection points were investigated. Further studies were undertaken to verify the CFD predictions with the experimental hinge moment measurements. Hinge moment results from the experimental data and the theoretical data closely correlated with less than …

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 …

Analytic Confusion Matrix Bounds For Fault Detection And Isolation Using A Sum-Of-Squared-Residuals Approach, Daniel J. Simon, Donald L. Simon

Electrical and Computer Engineering Faculty Publications

Given a system which can fail in 1 of n different ways, a fault detection and isolation (FDI) algorithm uses sensor data to determine which fault is the most likely to have occurred. The effectiveness of an FDI algorithm can be quantified by a confusion matrix, also called a diagnosis probability matrix, which indicates the probability that each fault is isolated given that each fault has occurred. Confusion matrices are often generated with simulation data, particularly for complex systems. In this paper, we perform FDI using sum-of-squared residuals (SSRs). We assume that the sensor residuals are s-independent and Gaussian, which …

Development Of A Meshless Method To Solve Compressible Potential Flows, Alejandro Ramos

Master's Theses

The utility of computational fluid dynamics (CFD) for solving problems of engineering interest has experienced rapid growth due to the improvements in both memory capacity and processing speed of computers. While the capability now exists for the solution of the Navier-Stokes equations about complex and complete aircraft configurations, the bottleneck within the process is the time consuming task of properly generating a mesh that can accurately solve the governing partial differential equations (PDEs). This thesis explored two numerical techniques that attempt to circumvent the difficulty associated with the meshing process by solving a simplified form of the continuity equation within …

A Three Dimensional Vortex Particle-Panel Code For Modeling Propeller-Airframe Interaction, Jacob S. Calabretta

Master's Theses

Analysis of the aerodynamic effects of a propeller flowfield on bodies downstream of the propeller is a complex task. These interaction effects can have serious repercussions for many aspects of the vehicle, including drag changes resulting in larger power requirements, stability changes resulting in adjustments to stabilizer sizing, and lift changes requiring wing planform adjustments.

Historically it has been difficult to accurately account for these effects at any stage during the design process. More recently methods using Euler solvers have been developed that capture interference effects well, although they don't provide an ideal tool for early stages of aircraft design, …

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 …

Novel Inverse Airfoil Design Utilizing Parametric Equations, Kevin A. Lane

Master's Theses

The engineering problem of airfoil design has been of great theoretical interest for almost a century and has led to hundreds of papers written and dozens of methods developed over the years. This interest stems from the practical implications of airfoil design. Airfoil selection significantly influences the application's aerodynamic performance. Tailoring an airfoil profile to its specific application can have great performance advantages. This includes considerations of the lift and drag characteristics, pitching moment, volume for fuel and structure, maximum lift coefficient, stall characteristics, as well as off-design performance.

A common way to think about airfoil design is optimization, the …

A Novel Telescopic Boom Deployment System For Use In Upper Atmosphere Research, Mark Wylie, Paul Duffy, Dinesh Vather, Johnalan Keegan, Stephen Curran

Conference Papers

Typical measurement probe deployment systems on sounding rockets employ hinged booms which extend the probes away from the rocket. This configuration often has a significant mass and may require a considerable amount of the rocket’s valuable payload volume. In an effort to reduce both mass and volume, the DIT Space Research Group have designed a light weight carbon fibre telescopic boom system, compatible with measurement probes commonly used in upper atmosphere research. Our design has been selected to be tested on a suborbital space flight onboard the REXUS 9 sounding rocket in March 2011. The purpose of this test is …

Numerical Simulation Of A Liquid Jet Atomization And Break-Up Using Ansys-Cfx 12.0, Yash Akhil Bhatt

Master's Theses - Daytona Beach

Break-up and atomization characteristics of JetA liquid fuel were investigated numerically. The results have been compared to various experimental results to evaluate the accuracy of the numerical model. The CFD code ANSYS-CFX 12.0 was used to carry out the steady state analysis at different time scales. A comparison between the atomization characteristics of a pressure jet atomizer and an air-blast atomizer is shown. By employing a Lagrangian particle tracking method to track the path of the liquid particles, the liquid jet/spray phenomena was studied in light of low and high back pressure environments. The 'BLOB' primary atomization model and the …

Assessing The V2-F Turbulence Models For Circulation Control Applications, Travis M. Storm

Master's Theses

In recent years, airports have experienced increasing airport congestion, partially due to the hub-and-spoke model on which airline operations are based. Current airline operations utilize large airports, focusing traffic to a small number of airports. One way to relieve such congestion is to transition to a more accessible and efficient point-to-point operation, which utilizes a large web of smaller airports. This expansion to regional airports propagates the need for next-generation low-noise aircraft with short take-off and landing capabilities. NASA has attacked this problem with a high-lift, low-noise concept dubbed the Cruise Efficient Short Take-Off and Landing (CESTOL) aircraft. The goal …

High Order Finite Elements For Lagrangian Computational Fluid Dynamics, Truman Everett Ellis

Master's Theses

A general finite element method is presented to solve the Euler equations in a Lagrangian reference frame. This FEM framework allows for separate arbitrarily high order representation of kinematic and thermodynamic variables. An accompanying hydrodynamics code written in Matlab is presented as a test-bed to experiment with various basis function choices. A wide range of basis function pairs are postulated and a few choices are developed further, including the bi-quadratic Q2-Q1d and Q2-Q2d elements. These are compared with a corresponding pair of low order bi-linear elements, traditional Q1-Q0 and sub-zonal pressure Q1-Q1d. Several test problems are considered including static convergence …

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 …

Stability Of Fully Nonlinear Stokes Waves On Deep Water: Part 1. Perturbation Theory, Shahrdad Sajjadi, David L. Ross

Publications

We consider a full set of harmonics for the Stokes wave in deep water in the absence of viscosity, and examine the role that higher harmonics play in modifying the classical Benjamin-Feir instability. Using a representation of the wave coefficients due to Wilton, a perturbation analysis shows that the Stokes wave may become unbounded due to interactions between the N^th harmonic of the primary wave train and a set of harmonics of a disturbance. If the frequency of the n^th harmonic is denoted Ꙍ_n = Ꙍ(1 ± ꭉ) then instability will occur if

√2 k n^{n …}

Particle Size Control For Piv Seeding Using Dry Ice, Brian T. Love

Theses and Dissertations

Particle image velocimetry (PIV) has been carried out using solid carbon dioxide (CO₂) particles as the seed material to continue the development of clean seeding for use in large-scale, closed-circuit tunnels. Testing occurred in two wind tunnels at subsonic and supersonic speeds using dry ice particles generated by allowing liquefied CO₂ to expand from a small diameter injector tube through a larger diameter shroud tube. The particles were injected into the plenum and discrete solid particles, suitable for PIV measurements, were present in the test section. Data on particle size were first collected using a Malvern particle …

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 …

Investigation Of A Novel Compact Vibration Isolation System For Space Applications, Steven D. Miller

Theses and Dissertations

A novel compact vibration isolation system was designed, built, and tested for the Space Chromotomography Experiment (CTEx) being built by Air Force Institute of Technology (AFIT) researchers. CTEx is a multifunctional experimental imaging chromotomographic spectrometer designed for flight on the International Space Station (ISS) and is sensitive to jitter caused by vibrations both through the support structure as well as those produced on the optical platform by rotating optical components. CTEx demands a compact and lightweight means of vibration isolation and suppression from the ISS structure. Vibration tests conducted on an initial isolator design resulted in changes in the chosen …

Development Of Morphing Aircraft Structure Using Smp, Soo-Chan Jee

Theses and Dissertations

The U.S Air Force needs new aircraft which provide longer flight time, less fuel consumption, better aerodynamics in order to perform Air Force missions successfully as the mission environment changes rapidly. A morphing wing aircraft is considered as a potential new aircraft for those missions. This thesis explores Shape Memory Polymer (SMP) properties test results and its application for morphing wing skin. Several SMP composite laminates were considered for investigating shape changing characteristics required for morphing skin. The braided composite preforms used in making SMP composites were explored in morphing wing operating system based on the results of property tests. …

Back-Pressure Effect On Shock-Train Location In A Scramjet Engine Isolator, Richard I. Paek

Theses and Dissertations

The isolator of the scramjet decelerates the incoming high Mach flow to a lower Mach number and stabilizes the flow before it enters the combustor. Because of the unsteady combustion phenomenon and inconsistent completeness of the combustion, pressures within the combustor can vary drastically. These pressure variations can propagate forward and affect the flow field in the isolator - worst case unstarting the inlet. In this research, the shock train location versus the back-pressure is examined experimentally. The back-pressure is artificially created by symmetric (top & bottom) ramps that can close the flow area. Raising/lowering ramps result in higher/lower back-pressure. …

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 …

Cfd Analysis Of Experimental Wing And Winglet For Falconlaunch 8 And The Exfit Program, Benjamin P. Switzer

Theses and Dissertations

Reusable launch vehicles have many benefits over their expendable counterparts. These benefits range from cost reductions to increased functionality of the vehicles. Further research is required in the development of the technology necessary for reusable launch vehicles to come to fruition. The Air Force Institute of Technology’s future involvement in the ExFIT program will entail designing and testing of a new wing tip mounted vertical stabilizer in the hypersonic regime. One proposed venue for experimentation is to utilize the United States Air Force Academy’s FalconLAUNCH Program which annually designs, builds, and launches a sounding rocket capable of reaching hypersonic speeds. …