Publications by Type: Conference Proceedings

2015
D. Pylorof and Bakolas, E., “

Nonlinear Control under Polytopic Input Constraints with Application to the Attitude Control Problem

,” American Control Conference 2015. Chicago, 2015.PDF icon acc2015_dpeb.pdf
J. Selvakumar and Bakolas, E., “

Optimal Guidance of the Isotropic Rocket in a Partially Uncertain Flow

,” European Control Conference, 2015. Linz, Austria, 2015.PDF icon ecc15_jseb.pdf
D. Pylorof and Bakolas, E., “

Tracking a Maneuvering Target with an Underactuated UAV in the SE(3) Space

,” AIAA Guidance, Navigation, and Control Conference, AIAA Science and Technology Forum 2015 . Kissimee,Florida, 2015.
G. A. Mack, Tinney, C. E., and Ruf, J. H., “RELIABLE METHODS FOR PREDICTING THE SOUND FROM CLUSTERED ROCKET NOZZLES,” 15th European Turbulence Conference. Delft, The Netherlands, 2015.Abstract
High area ratio rockets generate strong vibro-acoustic loads primarily during transient operations, like start-up and shut-down of the engine. These loads can adversely affect the launch vehicle and its payload. Thus, an accurate prediction of the loads produced during engine start-up is pertinent to the safety and reliability of the launch vehicle. The present work focuses on developing a robust framework for predicting these loads using laboratory scale rocket nozzles tested in the fully anechoic chamber at The University of Texas at Austin. This encompasses corrections for the observer position relative to the prominent source region, as well as scaling factors to correct for geometric factors. The test campaign encompasses single, two, three and four nozzle clusters, as well as differences in nozzle geometry and operating conditions (nozzle pressure ratio).
PDF icon c2015etc15-delftmack.pdf
A. Canchero, Rojo, R., Tinney, C. E., Murray, N., and Ruf, J. H., “SHADOWGRAPHY OF THE END-EFFECTS REGIME PRODUCED BY CLUSTERED ROCKETS,” 15th European Turbulence Conference. Delft, The Netherlands, 2015.Abstract
The plume produced by a cluster of two high area-ratio thrust optimized parabolic contour nozzles is visualized by way of retroreflective shadowgraphy. Both steady and transient operations of the nozzles (start-up and shut-down) were conducted in the anechoic chamber and high speed flow facility at The University of Texas at Austin. Both nozzles exhibit free shock separated flow, restricted shock separated flow and an end-effects regime prior to flowing full. Radon transforms of the shadowgraphy images are used to identify the locations in the flow where sound waves are being generated. During these off design operations of the nozzles, most sound waves are generated by turbulence interactions with the shock cells located in the supersonic annular plume. During the end-effects regime, this supersonic annular plume is shown to flap violently, thus providing a first principals understanding of the sources of most intense loads during engine ignition.
PDF icon c2015etc15-delftcanchero.pdf
S. Kelly, Torres-Verdín, C., and Balhoff, M., “Shale fluid transport in nanoscale networks: the competing roles of fluid properties, interfaces, and network geometry (Expanded Abstract),” Unconventional Resources Technology Conference (URTeC). San Antonio, Texas, July 20 – 22, 2015.
S. Kelly, Torres-Verdín, C., and Balhoff, M., “Shale fluid transport in nanoscale networks: the competing roles of fluid properties, interfaces, and network geometry (Expanded Abstract),” Unconventional Resources Technology Conference (URTeC). San Antonio, Texas, July 20 – 22, 2015.
W. Herrera, Wang, R., and Torres-Verdín, C., “Simulation and interpretation of LWD sonic measurements acquired in high-angle and horizontal wells (Expanded Abstract),” Society of Petrophysicists and Well Log Analysts (SPWLA) 56th Ann. Logging Symposium. Long Beach, CA, July 18-22, 2015.
W. Herrera, Wang, R., and Torres-Verdín, C., “Simulation and interpretation of LWD sonic measurements acquired in high-angle and horizontal wells (Expanded Abstract),” Society of Petrophysicists and Well Log Analysts (SPWLA) 56th Ann. Logging Symposium. Long Beach, CA, July 18-22, 2015.
S. Huang and Torres-Verdín, C., “Sonic spatial sensitivity functions and inversion-based layer-by-layer interpretation of borehole sonic logs (Expanded Abstract),” Society of Petrophysicists and Well Log Analysts (SPWLA) 56th Ann. Logging Symposium. Long Beach, CA, July 18-22, 2015.
S. Huang and Torres-Verdín, C., “Sonic spatial sensitivity functions and inversion-based layer-by-layer interpretation of borehole sonic logs (Expanded Abstract),” Society of Petrophysicists and Well Log Analysts (SPWLA) 56th Ann. Logging Symposium. Long Beach, CA, July 18-22, 2015.
C. E. Tinney, Canchero, A., Rojo, R., Mack, G., Murray, N. E., and Ruf, J. H., “The Sound-field Produced by Clustered Rockets During Startup,” Whither Turbulence and Dig Data for the 21st Century. Symposium held at the Institute dEtudes Scientifques de Cargese, Corsica, France, April 20-24, (Springer Hardbound Volume, DOI: 10.1007/978-3-319-41217-7), 2015.Abstract
The vibroacoustic loads produced by a cluster of two large area-ratio thrust optimized parabolic contour nozzles are studied over a range of pressure ratios encompassing free-shock separated flow, restricted shock separated flow and the end-effects-regime. The rocket plume is visualized using a retroreflective shadowgraphy system while an experimentally validated RANS model provides insight into the internal flow and shock structure patterns. Pressure loads that form on the base of the vehicle (behind the nozzles) are then measured using a eighth-inch microphone, as most of these loads are caused by high intensity sound waves produced by the rocket nozzle flow. The objective of the study is to provide a direct link between the sources of most intense vibro-acoustic loads that form during the ignition of high area ratio rocket nozzle clusters.
B. Ghanbarian and Daigle, H., “Thermal conductivity modeling in variably saturated porous media,” AGU Fall Meeting Abstracts. 2015.
H. Lee and Torres-Verdín, C., “Thermodynamically consistent estimation of hydrocarbon composition from nuclear and magnetic resonance measurements (Expanded Abstract),” Society of Petrophysicists and Well Log Analysts (SPWLA) 56th Ann. Logging Symposium. Long Beach, CA, July 18-22, 2015.
H. Lee and Torres-Verdín, C., “Thermodynamically consistent estimation of hydrocarbon composition from nuclear and magnetic resonance measurements (Expanded Abstract),” Society of Petrophysicists and Well Log Analysts (SPWLA) 56th Ann. Logging Symposium. Long Beach, CA, July 18-22, 2015.
P. Sayar and Torres-Verdín, C., “Using sonic and resistivity effective medium theories to quantify the influence of rock fabric on the mechanical properties of organic mudrocks (Expanded Abstract),” Unconventional Resources Technology Conference (URTeC). San Antonio, Texas, July 20 – 22, 2015.
P. Sayar and Torres-Verdín, C., “Using sonic and resistivity effective medium theories to quantify the influence of rock fabric on the mechanical properties of organic mudrocks (Expanded Abstract),” Unconventional Resources Technology Conference (URTeC). San Antonio, Texas, July 20 – 22, 2015.
L. Bai, Li, C., Darnault, C. J. G., Korte, C., Ladner, D., and Daigle, H., “Wetting and Interfacial Tension Dynamics of Oil-Nanofluids-Surface Minerals System,” AGU Fall Meeting Abstracts. 2015.
2014
R. Fievet, Tinney, C. E., Baars, W. J., and Hamilton, M. F., “Acoustic waveforms produced by a laboratory scale supersonic jet,” 20th AIAA/CEAS Aeroacoustics Conference, AIAA Paper 2014-2906. Atlanta, Georgia. USA, 2014.Abstract
The spatial evolution of acoustic waveforms produced by a Mach 3 jet are investigated using both 1/4 inch and 1/8 inch pressure field microphones located along rays emanating from the post potential core where the peak sound emission is found to occur. The measurements are acquired in a fully anechoic chamber where ground, or other large surface reflections are minimal. The calculation of the OASPL along an arc located at 95 jet diameters using 120 planar grid measurements are shown to collapse remarkably well when the arc array is centered on the post potential core region. Various statistical metrics, including the quadrature spectral density, number of zero crossings, the skewness of the pressure time derivative and the integral of the negative part of the quadrature spectral density, are exercised along the peak emission path. These metrics are shown to undergo rapid changes within 2 meters from the source regions of this laboratory scale jet. The sensitivity of these findings to both transducer size and humidity effects are discussed. A visual extrapolation of these nonlinear metrics toward the jet shear layer suggests that these waveforms are initially skewed at the source. An experimentally validated wave packet model is used to confirm the location where the pressure decay law transition from cylindrical to spherical. It is then used to estimate the source intensity which is required to predict the effective Gol’dberg number. 1
PDF icon c2014aiaa-atlantafievet-2906.pdf
T. M. Truskett, Johnston, K. P., Maynard, J. A., Borwankar, A. U., Murthy, A. K., Stover, R. J., Wilson, B. K., Dinin, A. K., Laber, J. R., and Gourisankar, S., “Assembling nanoclusters in water for therapy or imaging,” ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, vol. 247. AMER CHEMICAL SOC 1155 16TH ST, NW, WASHINGTON, DC 20036 USA, 2014.

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