Engineering Commons^™

Analysis And Comparison Of Effects Of An Airfoil Or A Rod On Supersonic Cavity Flow., William Leland Fowler

Masters Theses

The effects of an airfoil at different angles of attack and a circular cylindrical rod within the edge of the boundary layer flow at the leading edge of a cavity as a device for controlling the large pressure fluctuations (resonance tones) in the cavity were investigated. The airfoil results were compared with the rod in crossflow method positioned at the same leading edge location. The cavity used for testing corresponded to a length to depth ratio, L/D of 11.0/2.25 with a length to width ratio, L/W of 11.0/3.00 at a freestream Mach 1.84 flow. The study included measurements of dynamic …

Automating The Data Reduction Process For More Efficient Flight Tests And Reducing The Time From Days To Hours, Joseph Kenneth Young

Masters Theses

The University of Tennessee Space Institute’s (UTSI) active airborne science program often requires extensive modification to its fleet of aircraft in order to meet mission and customer requirements. These modifications can alter the flight characteristics of the aircraft. In order to determine if the aircraft is safe to fly after modification and to find any new flight characteristics resulting from the modifications, the flight test engineer (FTE) must plan and conduct limited flight testing on the aircraft and evaluate the resulting data to ensure safety of flight. The more efficient the data reduction and analysis process the quicker the aircraft …

A Performance Analysis Of A Rocket Based Combined Cycle (Rbcc) Propulsion System For Single-Stage-To-Orbit Vehicle Applications, Nehemiah Joel Williams

Masters Theses

Rocket-Based Combined Cycle (RBCC) engines combine the best performance characteristics of air-breathing systems such as ramjets and scramjets with rockets with the goal of increasing payload/structure and propellant performance and thus making LEO more readily accessible. The idea of using RBCC engines for Single-Stage-To-Orbit (SSTO) trans-atmospheric acceleration is not new, but has been known for decades. Unfortunately, the availability of detailed models of RBCC engines is scarce. This thesis addresses the issue through the construction of an analytical performance model of an ejector rocket in a dual combustion propulsion system (ERIDANUS) RBCC engine. This performance model along with an atmospheric …

Evaluation Of The Aerodynamics Of An Aircraft Fuselage Pod Using Analytical, Cfd, And Flight Testing Techniques, William C. Moonan

Masters Theses

The purpose of this study is to investigate the execution and validity of various predictive methods used in the design of the aerodynamic pod housing NASA’s Marshall Airborne Polarimetric Imaging Radiometer (MAPIR) on the University of Tennessee Space Institute’s Piper Navajo research aircraft. Potential flow theory and wing theory are both used to analytically predict the lift the MAPIR Pod would generate during flight; skin friction theory, empirical data, and induced drag theory are utilized to analytically predict the pod’s drag. Furthermore, a simplified computational fluid dynamics (CFD) model was also created to approximate the aerodynamic forces acting on the …

Propagation Of Periodic Waves Using Wave Confinement, Paula Cysneiros Sanematsu

Masters Theses

This thesis studies the behavior of the Eulerian scheme, with "Wave Confinement" (WC), when propagating periodic waves. WC is a recently developed method that was derived from the scheme "vorticity confinement" used in fluid mechanics, and it efficiently solves the linear wave equation. This new method is applicable for numerous simulations such as radio wave propagation, target detection, cell phone and satellite communications.

The WC scheme adds a nonlinear term to the discrete wave equation that adds stability with negative and positive diffusion, conserves integral quantities such as total amplitude and wave speed, and it allows wave propagation over long …

Evaluation Of Geometric Scale Effects For Scramjet Isolators, Jaime Enrique Perez

Masters Theses

A numerical analysis was conducted to study the effects of geometrically scaling scramjet inlet-combustor isolators. Three-dimensional fully viscous numerical simulation of the flow inside constant area rectangular ducts, with a downstream back pressure condition, was analyzed using the SolidWorks Flow Simulation software. The baseline, or 1X, isolator configuration has a 1” x 2.67” cross section and 20” length. This baseline configuration was scaled up based on the 1X configuration mass flow to 10X and 100X configurations, with ten and one hundred times the mass flow rate, respectively. The isolator aspect ratio of 2.67 was held constant for all configurations. To …

Nonlinear Acoustics Of Piston-Driven Gas-Column Oscillations, Andrew William Wilson

Masters Theses

The piston-driven oscillator is traditionally modeled by directly applying boundary conditions to the acoustic wave equations; with better models re-deriving the wave equations but retaining nonlinear and viscous effects. These better models are required as the acoustic solution exhibits singularity near the natural frequencies of the cavity, with an unbounded (and therefore unphysical) solution. Recently, a technique has been developed to model general pressure oscillations in propulsion systems and combustion devices. Here, it is shown that this technique applies equally well to the piston-driven gas-column oscillator; and that the piston experiment provides strong evidence for the validity of the general …

Development And Use Of A Computer Program “Hyper-N” To Predict The Performance Of Air Vehicles Traveling At Hypersonic Speeds, Younes Baalla

Masters Theses

Abstract The main objective of this thesis was to develop a method than can be used to approximate the pressure forces on air vehicles traveling at hypersonic speed (Mach number > 5). The aerodynamic forces such as lift and drag were calculated from the pressure values on the surface of the airplane. Pitching moment was also tabulated. This work was initiated based on the idea of developing a flow solver proficient and capable of providing aerodynamic data (lift and drag look-up tables) for hypersonic air vehicles that can be fed to a flight simulator (used by the Aviation Systems Department) at …

A General Simulation Of An Air Ejector Diffuser System, Derick Thomas Daniel

Masters Theses

A computer model of a blow-down free-jet hypersonic propulsion test facility exists to validate facility control systems as well as predict problems with facility operation. One weakness in this computer model is the modeling of an air ejector diffuser system. Two examples of facilities that could use this ejector diffuser model are NASA Langley Research Center's 8-ft High Temp. Tunnel (HTT) and the Aero-Propulsion Test Unit (APTU) located at Arnold Engineering Development Center. Modeling an air ejector diffuser system for a hypersonic propulsion test facility includes modeling three coupled systems. These are the ejector system, the primary free-jet nozzle that …

Capstone Design: Energy Efficient Windows Triple Pane Window Analysis, Michael S. Kee, Drew Ryan Hughes, Amanda Michele Lee, Michael Mcmillan, Jake Eric Plewa

Chancellor’s Honors Program Projects

No abstract provided.

Theoretical Models For Wall Injected Duct Flows, Tony Saad

Doctoral Dissertations

This dissertation is concerned with the mathematical modeling of the flow in a porous cylinder with a focus on applications to solid rocket motors. After discussing the historical development and major contributions to the understanding of wall injected flows, we present an inviscid rotational model for solid and hybrid rockets with arbitrary headwall injection. Then, we address the problem of pressure integration and find that for a given divergence free velocity field, unless the vorticity transport equation is identically satisfied, one cannot find an analytic expression for the pressure by direct integration of the Navier-Stokes equations. This is followed by …

Team Volocity, Beth Clement, William Schuman

Chancellor’s Honors Program Projects

No abstract provided.

An Empirical Model Of Thermal Updrafts Using Data Obtained From A Manned Glider, Christopher E. Childress

Masters Theses

Various methods have been used, including airborne radars, LIDAR, observation of flying birds, towers, tethered balloons, and aircraft to gain both a qualitative and quantitative representation of how heat and moisture are transported to higher altitudes and grow the boundary or mixing layer by thermal updrafts. This paper builds upon that research using an instrumented glider to determine the structure and build a mathematical model of thermals in a desert environment. During these flights, it was discovered that the traditional view of a thermal as a singular rising plume of air did not sufficiently explain what was being observed, but …