Aerospace Engineering Commons^™

Analysis Of Turbulent Flow Behavior In Helicopter Rotor Hub Wakes, Forrest Mobley

Masters Theses

The rotor hub is one of the most important features of all helicopters, as it provides the pilot a means for controlling the vehicle by changing the characteristics of the main and tail rotors. The hub also provides a structural foundation for the rotors and allows for the rotor blades to respond to aerodynamic forces while maintaining controllability and stability. Due to the inherent geometry and high rate of rotation, the rotor hub in its current form acts a large bluff body and is the primary source of parasite drag on the helicopter, despite its relatively small size. The rotor …

Development Of A Multi-Jointed Wing Surface Mover, Collin Arthur Strassburger

Masters Theses

The field of ornithopter research has reached a point where it has become commonplace for Computational Fluid Dynamics (CFD) solvers to have built-in capabilities for rigid solid body motion. This is suitable for micro air vehicles (MAVs) yet is often not exible enough to model wings with dynamic internal structure, such as the wings of birds and bats. There is currently no program available to perform the surface motion of a wing which has multiple independently moving joints. The code, detailed in this paper, provides the user with this type of capability. The bone lengths, joint angle properties, and thickening …

A Numerical Study Of The Limiting Cases Of Cylinder-Induced Shock Wave/Boundary Layer Interactions, Stefen Albert Lindorfer

Masters Theses

One of the limiting factors in the design of supersonic and hypersonic vehicles remains the prediction and control of the high aerodynamic, thermodynamic, acoustic, and structural loads generated by a shock wave/boundary layer interaction (SWBLI or SBLI). In conjunction with an experimental campaign produced within the research group, a numerical study was performed using a semi-infinite cylinder to generate a SWBLI at Mach 1.88 with both laminar and turbulent boundary layers. The goals were not only to better understand the complex flow surrounding the cylinder-induced turbulent interaction, but also to establish the interaction bounds of the limiting cases of a …

Development And Verification Of A Navier-Stokes Solver With Vorticity Confinement Using Openfoam, Austin Barrett Kimbrell

Masters Theses

Vorticity Confinement (VC) is a numerical technique which enhances computation of fluid flows by acting as negative diffusion within the limit of vortical regions, preventing the inherent numerical dissipation present with conventional methods. VC shares similarities with large eddy simulation (LES), but its behavior is based on a stable negative dissipation of vortical structures controlled by the automatic balance between two parameters, μ [mu] and ε [epsilon].

In this thesis, three-dimensional, parallel-computing Navier-Stokes solvers with VC are developed using the OpenFOAM computational framework. OpenFOAM is an open-source collection of C++ libraries developed for computational fluid dynamics. Object-oriented programming concepts are …

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 …