Aerodynamics and Fluid Mechanics Commons^™

First-Year Project Experience In Aerospace: Apogee Determination Of Model Rockets With Explicit Consideration Of Drag Effect, Hüseyin Sarper, Drew Landman, Linda Vahala

Electrical & Computer Engineering Faculty Publications

This paper describes a student team project using model rockets and engines to learn engineering solution methods for determining the apogee of model rocket when the drag effect is considered explicitly instead of estimating its effect later. Model rocketry is a powerful tool for instructors who wish to incorporate science, engineering, and mathematics into a fun, engaging, and challenging activity for the students. The apogee can be determined using a number of distinct methods: trigonometry, onboard altimeters, analytical calculations, and simulation. This paper emphasizes numerical analytical solution using spreadsheet programming instead of a full analytical solution that requires higher mathematics. …

The Aerodynamic And Dynamic Loading Of A Slender Structure By An Impacting Tornado-Like Vortex: The Influence Of Relative Vortex-To-Structure Size On Structural Loading, Matthew Nicholas Strasser

Graduate Theses and Dissertations

Structural loading produced by an impacting vortex is a hazardous phenomenon that is encountered in numerous applications ranging from the destruction of residences by tornados to the chopping of tip vortices by rotors. Adequate design of structures to resist vortex-induced structural loading necessitates study of the phenomenon that control the structural loading produced by an impacting vortex. This body of work extends the current knowledge base of vortex-structure interaction by evaluating the influence of the relative vortex-to-structure size on the structural loading that the vortex produces. A computer model is utilized to directly simulate the two-dimensional impact of an impinging …

Direct Adaptive Control For Stability And Command Augmentation System Of An Air-Breathing Hypersonic Vehicle, Ron Aditya

Doctoral Dissertations and Master's Theses

In this paper we explore a Direct Adaptive Control scheme for stabilizing a non-linear, physics based model of the longitudinal dynamics for an air breathing hypersonic vehicle. The model, derived from first principles, captures the complex interactions between the propulsion system, aerodynamics, and structural dynamics. The linearized aircraft dynamics show unstable and non-minimum phase behavior. It also shows a strong short period coupling with the fuselage-bending mode. The value added by direct adaptive control and the theoretical requirements for stable convergent operation is displayed. One of the main benefits of the Directive Adaptive Control is that it can be implemented …

Aerodynamic Trade Study Of Compound Helicopter Concepts, Julian Roche

Doctoral Dissertations and Master's Theses

The relative performance attributes of compound helicopter concepts have been examined, including their potential for meeting the requirements of several challenging mission profiles. For each concept, which included lift and/or propulsive compounding, a suite of aerodynamic performance models was developed using energy methods. In the case of a lift-compounded concept, an aerodynamic model representing the force interaction effects of the main rotor wake with the wing was also developed. Models of a conventional helicopter and of a tiltrotor were implemented as well, and the results used as a datum for comparison. In each case, the predictive capabilities of the model …

Numerical Study Of Synthetic-Jet Actuation Effect On Airfoil Trailing Edge Noise, Marco Sansone

Doctoral Dissertations and Master's Theses

The current study conducts numerical simulations to assess the possibility of employing Synthetic Jet Actuators (SJAs) as active noise control devices for reduction of airfoil acoustic radiation. High-accuracy numerical efforts employ a sixth-order accurate Navier-Strokes solver implementing a low-pass filtering of poorly resolved high-frequency solution content to retain numerical accuracy and stability over the range of transitional flow regimes. In the adopted numerical procedure, the actuator is modeled without its resonator cavity through imposing a simple fluctuating-velocity boundary condition at the bottom orifice of the actuator. The orifice cavity with the properly defined boundary condition is embedded into the airfoil …

Effects Of Magnetic Fields On Magnetohydrodynamic Cylindrical And Spherical Richtmyer-Meshkov Instability, Wouter Mostert, Vincent Wheatley, Ravi Samtaney, Dale I. Pullin

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The effects of seed magnetic fields on the Richtmyer-Meshkov instability driven by converging cylindrical and spherical implosions in ideal magnetohydrodynamics are investigated. Two different seed field configurations at various strengths are applied over a cylindrical or spherical density interface which has a single-dominant-mode perturbation. The shocks that excite the instability are generated with appropriate Riemann problems in a numerical formulation and the effect of the seed field on the growth rate and symmetry of the perturbations on the density interface is examined. We find reduced perturbation growth for both field configurations and all tested strengths. The extent of growth suppression …

Extending Gr While Moving Up To Supersonic Speeds Poses Challenges Requiring Innovations, Nihad E. Daidzic

Aviation Department Publications

Achieving true global range requires new ideas in lightweight aircraft structures, progress in transonic and supersonic aerodynamics and breakthroughs in low-SFC propulsion.

Axisymmetric Bi-Propellant Air Augmented Rocket Testing With Annular Cavity Mixing Enhancement, Allen A. C. Capatina

Master's Theses

Performance characterization was undertaken for an air augmented rocket mixing duct with annular cavity configurations intended to produce thrust augmentation. Three mixing duct geometries and a fully annular cavity at the exit of the nozzle were tested to enable thrust comparisons. The rocket engine used liquid ethanol and gaseous oxygen, and was instrumented with sensors to output total thrust, mixing duct thrust, combustion chamber pressure, and propellant differential pressures across Venturi flow measurement tubes.

The rocket engine was tested to thrust maximum, with three different mixing ducts, three major combustion pressure sets, and a nozzle exit plane annular cavity (a …

Thrust Prediction For A Rotor Operating In A Ship Airwake, Mathew Thomas

Mechanical & Aerospace Engineering Theses & Dissertations

This report details work performed at Old Dominion University focused on developing a thrust prediction capability for a rotor operating in a ship airwake. The study has built upon previous experimental work utilizing particle image velocimetry-based velocity field measurements to quantify the degree of coupling in a simplified rotor/ship airwake experiment. Using the velocity field data of the previous study, a database was built representing the volume over the landing deck. Rotor thrust was computed using blade element methods and compared to direct load cell measurements and to a superposed velocity field. Results show that the blade element method has …

Analysis Of Hypersonic Vehicle Wakes, Matthew A. Kania

Theses and Dissertations

As advancements are made with ballistic missiles, particularly in the area of hypersonic bodies, there is a growing need to advance the methods of detecting these new ballistic weapons. As a result, the National Air and Space Intelligence Center has asked the Air Force Institute of Technology to examine the wake region behind hypersonic bodies. A thorough understanding of the aerothermal phenomena and the chemical reactions occurring in the wake region will enable an advancement of tracking hypersonic bodies. This research examined the wake region behind a hypersonic body using computational fluid dynamics.
This study used Pointwise® to develop a …

Development Of Cpanel, An Unstructured Panel Code, Using A Modified Tls Velocity Formulation, Christopher R. Satterwhite

Master's Theses

The use of panel codes in the aerospace industry dates back many decades. Recent advances in computer capability have allowed them to evolve, both in speed and complexity, to provide very quick solutions to complex flow fields. By only requiring surface discretization, panel codes offer a faster alternative to volume based methods, delivering a solution in minutes, as opposed to hours or days. Despite their utility, the availability of these codes is very limited due to either cost, or rights restrictions.

This work incorporates modern software development practices, such as unit level testing and version control, into the development of …

Application Of Wray-Agarwal Model To Turbulent Flow In A 2d Lid-Driven Cavity And A 3d Lid-Driven Box, Hakop J. Nagapetyan

McKelvey School of Engineering Graduate Student Theses & Dissertations

In this thesis, various turbulence models are used for simulating internal vortical flow, both turbulent and laminar, with large recirculation by considering the flow in a 2-D lid-driven square cavity and a 3-D lid driven cubic box. The accuracy of the newly developed Wray-Agarwal (WA) one equation turbulence model is compared against two well-known industry standard turbulence models; the Spalart-Allmaras (SA) and the Shear-Stress-Transport (SST) k-ω models. The simulations are performed by numerically solving the Reynolds-Averaged Navier-Stokes (RANS) equations in conjunction with WA, SA and SST k-ω models and comparing the results with the available experimental data and Large Eddy …

Dynamic Characteristics Of Biologically Inspired Hair Receptors For Unmanned Aerial Vehicles, Manohar Chidurala

LSU New Orleans Theses and Dissertations

The highly optimized performance of nature’s creations and biological assemblies has inspired the development of their engineered counter parts that can potentially outperform conventional systems. In particular, bat wings are populated with air flow hair receptors which feedback the information about airflow over their surfaces for enhanced stability and maneuverability during their flight. The hairs in the bat wing membrane play a role in the maneuverability tasks, especially during low-speed flight. The developments of artificial hair sensors (AHS) are inspired by biological hair cells in aerodynamic feedback control designs. Current mathematical models for hair receptors are limited by strict simplifying …

Dsmc Simulation Of Microstructure Actuation By Knudsen Thermal Force, Aaron Pikus, Israel Sebastiao, Andrew Strongrich, Alina Alexeenko

The Summer Undergraduate Research Fellowship (SURF) Symposium

In many industrial and research applications there is a need for vacuum sensors with higher accuracy and spatial resolution than what is currently available. Examples of target applications include high-altitude platforms, satellites and in-vacuum manufacturing processes such as freeze-drying of food and pharmaceuticals. In this connection, a novel pressure sensor, named Microelectromechanical In-plane Knudsen Radiometric Actuator (MIKRA), has been developed by at Purdue University. MIKRA is based on Knudsen thermal forces generated by rarefied flow driven by thermal gradients within the microstructure Thus, the goal of this work is to model the rarefied gas flow in the MIKRA sensor under …

High Pressure Combustion And Supersonic Jet Ignition For H2/Air, Michael G. Woodworth, Sayan Biswas, Li Qiao

The Summer Undergraduate Research Fellowship (SURF) Symposium

There are many incentives to increase the fuel efficiency of combustion processes. This paper looks at two available options to achieve this goal. The former aims to develop an experimental method that can analyze combustion at extremely high pressures to improve the understanding of high pressure H2/air combustion. Experimental data has been lacking a suitable combustion diagnostic to visualize high pressure combustion processes, making it difficult to improve the process. Improvement of x-ray diffraction tomography in a windowless combustor makes it possible to see flame propagation at high pressure. The procedure and chamber are still in the design phase, yet …

Characterization Of Sprays From Dual Impinging Jets On A Splash Plate, Christopher Vodney, Stephen Heister, Brandon Kan, David Stechmann

The Summer Undergraduate Research Fellowship (SURF) Symposium

The use of splash plates and dual impinging liquid jets are common methods for fuel atomization, but the combination of these methods has not been explored. The goal of this experiment is to analyze how splash plate position and orientation affect the spray geometry for this combined method. The spray patterns are observed for a single jet against a splash plate and two orientations of dual impinging jets against a splash plate. For all three cases, the spray patterns are analyzed for various splash plate angles between 30 and 60 degrees relative to the jet centerline. For the dual impinging …

Book Review: High G Flight - Physiological Effects And Countermeasures, Stefan Kleinke

International Journal of Aviation, Aeronautics, and Aerospace

This review provides insight on the content and a review of the quality of the recent release of High G Flight - Physiological Effects and Countermeasures from Ashgate Publications.

This review does not reflect the views of IJAAA or ERAU. This work was not peer reviewed.

High G Flight - Physiological Effects and Countermeasures

Similarity Analysis Of A Swirling Counter-Flow, Jitesh Rane

Doctoral Dissertations and Master's Theses

Swirling counter-flows are used in numerous engineering applications, like combustion, heat exchangers, cyclonic separation and mixing, etc. These swirling counter-flows produce complex flow fields. It is important to study these types of flows in order to use them properly in many applications.

The present work provides insight into the flowfield inside a swirling counter-flow when the fluid is injected tangentially in a cylindrical container. A semi-analytical solution is developed by starting with the full Navier-Stokes equation and using a similarity analysis. A decaying swirl along the axis of the cylinder is assumed, which reduces the Navier-Stokes equations to first order …

On The Selection Of A Good Shape Parameter For Rbf Approximation And Its Application For Solving Pdes, Lei-Hsin Kuo

Dissertations

Meshless methods utilizing Radial Basis Functions~(RBFs) are a numerical method that require no mesh connections within the computational domain. They are useful for solving numerous real-world engineering problems. Over the past decades, after the 1970s, several RBFs have been developed and successfully applied to recover unknown functions and to solve Partial Differential Equations (PDEs).
However, some RBFs, such as Multiquadratic (MQ), Gaussian (GA), and Matern functions, contain a free variable, the shape parameter, c. Because c exerts a strong influence on the accuracy of numerical solutions, much effort has been devoted to developing methods for determining shape parameters which provide …

Flight Dynamics Nonlinearity Assessment Across A New Aerodynamic Attitude Flight Envelope, Ayman Muhammad Abdallah

Mechanical & Aerospace Engineering Theses & Dissertations

A new asymmetric level aerodynamic attitude flight envelope is introduced in this dissertation. The aerodynamic attitude envelope is an angle of attack vs. sideslip angle region which describes the extent of where an aircraft can sustain a steady slipping horizontal flight condition. The new envelope is thus an extension of the more common speed-altitude symmetric level flight envelope. This new envelope can be used for design requirements, dynamic analysis, control synthesis, or performance comparison. Moreover, this envelope provides enhanced insight into trimability-controllability limitations within the aircraft design model. The aerodynamic attitude flight envelope is constructed for a six degree of …