Summer 2013 Research and Participants

Content Creation Methods for Interactive eBooks featuring computationally intensive applications

REU Student: Logan Collins, Texas A&M University; John Angarita (Materials REU), Columbia University

Faculty Mentor: Dr. Jacques Richard

In this project, we have sought to facilitate learning through the improvement of educational interactive technologies. The current eBooks in today’s market do not use current products such as the iPhone and Android to engage in interactive versions of plain books, so our objective has been to explore the best method to take advantage of such tools. By analyzing the pros and cons of eBook formats, such as Kindle Format 8 and iBooks, we have concluded that ePub provides the ease of use desired along with the capability of including intensive interactive materials. We then researched what products are best suited to work with the latest version of ePub, and we found iBooks and Gitden Reader to fully support ePub3. On the other hand, many other readers still use ePub2 but we feel the lack of demand, as of now, for interactivity in their eBooks provides little motivation for use of the newer format. The process of then creating the textbook was started by creating a sample chapter, through which we were able to test the easiest methods to create the book and the various interactive capabilities of the user. We have laid the groundwork for the ease in creation of new interactive eBooks that can soon be assessed for efficiency. 

Graphical User Interface (GUI) for Computational Fluid Dynamics Solver

REU Student: Maytee Chantharayukhonthorn, University of Texas at Austin

Faculty Mentor: Dr. Paul Cizmas

Grad Student Mentor: Raymond Fontenot

While a command line interface has its advantages for the advanced user, for the general user, it is often confusing or unwieldy when interacting with programs. UNS3D, the computational fluid dynamics code developed by the research group of Dr. Paul Cizmas, currently uses only command line interaction. A GUI, or graphic user interface, relies on intuitive interactions with buttons, dropdown boxes, and other such elements to interface with the program. Commercial codes provide this functionality, and a basic GUI was available for UNS3D with limited features. This project thus aimed to improve upon and add additional functionality to the previously created GUI. The interface was changed from an organizational schema based on buttons to one based on tabs. More features were added to aide in user friendliness, such as organizing input files into projects and the ability to view some results of the code during execution. The GUI can also schedule several continued runs of UNS3D, creating a sequential or multiple run function. Many other features were also added, with the end result being a greatly improved user interface that is both more intuitive and increased in functionality than what was previously in place.

Effects of Rigidity on the Thrust Coefficient F A High Aspect Ratio Rigid and Flexible Pitching Panel for a Bio-inspired Caudal Fin Propulsor

REU Student: David Dang, Guillerma Vasquez-Garcia, Oregon State University

Faculty Mentors: Dr. Jacques Richard and Dr. Sharath S. Girimaji

Grad Student Mentor: Yi Yang

An air swimmer is a lighter-than-air vehicle, such as an air-ship that moves by imitating a fish but instead of swimming in water the air swimmer moves in air. Air swimmers can be used for transporting goods in remote areas where access is limited by ships or act as vehicles for rescue missions where the swimmer will be able to maneuver more effectively. Among the many aspects of the fish, the caudal fin is one of the most important parts on fish, since it provides the propulsion. The study of this research is the rigidity of the caudal fin and its effects on the coefficient of thrust. The study fixes the velocity throughout the trials while the dimensions of the panels maintain the aspect ratio (width/length) at 1.1, suggested by Bulcholz and Smits (2008) and Reynolds number to the fourth order. The Strouhal number range is from 0.1 to 0.4 and three panels with different stiffness are tested. The results show the most effective combination of frequency and amplitude to provide the highest coefficient of thrust.

Modeling Compressible Turbulent Plasma Flow

REU Student: Thomas S. Fowler IV, Youngstown State University

Faculty Mentors: Dr. Jacques Richard and Dr. Sharath S. Girimaji

Grad Student Mentor: Steven Anderson

A thorough understanding of plasma dynamics is critical for designing magnetic nozzles for plasma propulsion systems. In this study, we perform simulations of magnetic plasma vortex evolution using the Magnetohydrodynamic Gas-Kinetic Method (MGKM). Of particular interest is the canonical Orszag-Tang (OT) vortex flow. This is a standard benchmark test used to assess two dimensional MHD flow solvers and their ability to resolve supersonic turbulence and shocks. In the second part of the study, we examine the evolution of the OT vortices in a background turbulent velocity field. In the final step, an applied magnetic field is imposed to understand its affect upon a charged flow. Overall, this study aims to simulate some of the many magneto-fluid phenomena encountered in plasma nozzles.

Reinforcing and Improving a Balsa RC model Wind Tunnel Testing

REU Student: Lauryn Hoch, Texas A&M University

Faculty Mentor: Dr. Ed White

Grad Student Mentor:  Brian Rodgers

This paper offers a proposal to improve the capstone senior design course in the aerospace engineering department at Texas A&M University. The focus of improvement is the wind tunnel test in the second semester of the aircraft track of the senior design sequence. Currently, the wind tunnel test takes place in a small wind tunnel on campus, but the department is interested in moving the test off campus to the airport, where the Oran W. Nicks Low Speed Wind Tunnel is located. This move is an opportunity to enhance the wind tunnel test experience, as well as allow senior teams to test on their RC models, rather than on rapid prototype models. This move will significantly reduce the cost of materials used in the course, increase the amount of information that the senior teams can collect and give the teams a chance to act as customers at a professional engineering lab. Balsa airplanes, however, are not meant to last very long in a wind tunnel because of additional forces from the sting mount – they need to be reinforced in a way that resistive forces can be transferred away from the structure. The challenge that senior teams will face is that now they have to reinforce their balsa model so that it survives a wind tunnel test and they must be able to remove these reinforcements in order to fly.  This paper explains one method for creating reinforcing features that are easily inserted and removed from the balsa model without interfering with the structure. This method is very basic and can be adapted to fit the needs of any balsa flying model in a wind tunnel. 

Wavelet Analysis of the Laminar-Turbulent Transition in the Wake of a Roughness Trip

REU Student: Daniel Hsieh, University of California, Berkeley

Faculty Mentor: Dr. Ed White

Grad Student Mentor:  Ben Wilcox and Matt Kuester

Surface roughness such as paint or metal rivet heads can cause laminar boundary layers to become turbulent. Understanding how roughness affects laminar-turbulent transition could further reduce the viscous drag of airplanes, increasing their fuel economy and maximum speed. To investigate a simple case of roughness, we placed a cylindrical roughness element on a flat plate in a low-disturbance wind tunnel and measured the velocity in the roughness wake. We then performed Fourier and wavelet transforms on the fluctuations to search for patterns, including periodic turbulent bursts or high-amplitude frequencies. We detected Tollmien–Schlichting waves in the wake near the roughness. Farther downstream, there was less evidence of Tollmien–Schlichting waves, suggesting that the flow is fully turbulent in these regions. The evolution of turbulence was also observed while travelling spanwise across the wake.

Numerical Simulations of Transonic Plasma Expansion

REU Student: Gary Li, University of California, Berkeley

Faculty Mentors: Dr. Jacques Richard and Dr. Sharath S. Girimaji

Grad Student Mentor: Steven Anderson

Experimental studies of plasma exhaust plumes in magnetic nozzles are expensive and difficult to reproduce in ground-based labs. Therefore, design and development of electric propulsion schemes are highly dependent on numerical simulations. We continue development of a computational tool called the Magneto-Gas-Kinetic Method (MGKM) to more accurately simulate magnetic nozzle flows. MGKM utilizes the Gas- Kinetic Method, a robust fluid-kinetic Navier-Stokes solver developed by Xu (2000), and non-ideal Magnetohydrodynamics (MHD) to present new parametrical regimes of plasma flow simulation. We benchmark MGKM for 3D compressibility and the capability to resolve high Mach number flows using the spherical explosion with uniform applied magnetic field from Xu (2010). By varying the parameters of the flow, we also perform a parametric study of the idealized plasma expansion under a magnetic nozzle. This study helps to isolate specific mechanisms of magnetic nozzle physics such as resistive detachment and super-Alfvenic detachment. Further study and possible improvements to the code are also discussed.

Thermography of a Supersonic Flame Burner

REU Student: Ricardo T. Martinez, Texas A&M University

Faculty Mentor: Dr. Adonios N. Karpetis

Grad Student Mentor:  Dean W. Ellis

The objective of this work was to produce temperature maps of an existing supersonic flame burner. Knowledge of these temperature maps are needed to understand the method of flame holding inside the burner. The temperature maps were made using a state of the art Long Wave infrared camera (LWIR). Results were obtained by varying fuel-to-air ratios in vitiated. Change in temperature over time was also measured. The results of this research will contribute to the field of high speed combustion and advance knowledge of high-speed air breathing engines.  

Integration of a Pulse-Delay Generator and a Dye Laser for the Purpose of Performing Molecular Tagging Velocimetry in a Shock Tunnel

REU Student: Alexander A. Soderlund, University of Texas at Austin

Faculty Mentor: Dr. Rodney Bowersox

This report details the incorporation of a timing mechanism involving a pressure transducer and a pulse-delay generator with a dye laser to provide potential testing in a shock tube/tunnel. The shock tube itself was reinstated at the National Aerothermochemistry Laboratory, and was run multiple times to prove that it was operational. Transducers located along the tube were used to provide essential timing data as well as an accurate velocity measurement of the normal shock wave within the tunnel. Eventually, this timing and velocity information will be used to provide support and feasibility to the method of molecular tagging velocimetry (MTV) so a hypersonic flow field within a contraction-expansion nozzle attached to the shock tube can be studied.