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Summary of the High Ice Water Content (HIWC) RADAR Flight Campaigns

NASA Langley Research Center-Steven Harrah, Fred Proctor, Kristopher Bedka, Glenn Diskin, John B. Nowak
AMA-NASA Langley Research Center-Justin Strickland, Patricia Hunt
Published 2019-06-10 by SAE International in United States
NASA and the FAA conducted two flight campaigns to quantify onboard weather radar measurements with in-situ measurements of high concentrations of ice crystals found in deep convective storms. The ultimate goal of this research was to improve the understanding of high ice water content (HIWC) and develop onboard weather radar processing techniques to detect regions of HIWC ahead of an aircraft to enable tactical avoidance of the potentially hazardous conditions. Both HIWC RADAR campaigns utilized the NASA DC-8 Airborne Science Laboratory equipped with a Honeywell RDR-4000 weather radar and in-situ microphysical instruments to characterize the ice crystal clouds. The purpose of this paper is to summarize how these campaigns were conducted and highlight key results.The first campaign was conducted in August 2015 with a base of operations in Ft. Lauderdale, Florida. Ten research flights were made into deep convective systems that included Mesoscale Convective Systems (MCS) near the Gulf of Mexico and Atlantic Ocean, and Tropical Storms Danny and Erika near the Caribbean Sea. The radar and in-situ measurements from these ten flights were analyzed…
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Analysis and Automated Detection of Ice Crystal Icing Conditions Using Geostationary Satellite Datasets and In Situ Ice Water Content Measurements

SAE International Journal of Advances and Current Practices in Mobility

NASA Langley Research Center-Kristopher Bedka, Louis Nguyen
Met Analytics, Inc.-J. Walter Strapp
  • Journal Article
  • 2019-01-1953
Published 2019-06-10 by SAE International in United States
Recent studies have found that high mass concentrations of ice particles in regions of deep convective storms can adversely impact aircraft engine and air probe (e.g. pitot tube and air temperature) performance. Radar reflectivity in these regions suggests that they are safe for aircraft penetration, yet high ice water content (HIWC) is still encountered. The aviation weather community seeks additional remote sensing methods for delineating where ice particle (or crystal) icing conditions are likely to occur, including products derived from geostationary (GEO) satellite imagery that is now available in near-real time at increasingly high spatio-temporal detail from the global GEO satellite constellation. A recent study using a large sample of co-located GEO satellite and in-situ isokinetic evaporator probe (IKP-2) total water content (TWC) datasets found that optically thick clouds with tops near to or above the tropopause in close proximity (≤ 40 km) to convective updrafts were most likely to contain high TWC (TWC ≥ 1 g m-3). These parameters are detected using automated algorithms and combined to generate a HIWC probability (PHIWC) product at…
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Radar Detection of High Concentrations of Ice Particles - Methodology and Preliminary Flight Test Results

NASA Langley Research Center-Steven Harrah, Fred Proctor
AMA - NASA Langley Research Center-Justin Strickland, Patricia Hunt, George Switzer
Published 2019-06-10 by SAE International in United States
High Ice Water Content (HIWC) has been identified as a primary causal factor in numerous engine events over the past two decades. Previous attempts to develop a remote detection process utilizing modern commercial radars have failed to produce reliable results. This paper discusses the reasons for previous failures and describes a new technique that has shown very encouraging accuracy and range performance without the need for any modifications to industry’s current radar design(s). The performance of this new process was evaluated during the joint NASA/FAA HIWC RADAR II Flight Campaign in August of 2018. Results from that evaluation are discussed, along with the potential for commercial application, and development of minimum operational performance standards for future radar products.
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Random Variable Estimation and Model Calibration in the Presence of Epistemic and Aleatory Uncertainties

SAE International Journal of Materials and Manufacturing

NASA Langley Research Center-Luis G. Crespo, Sean P. Kenny
Imperial College London-Audrey Gaymann, Marco Pietropaoli, Francesco Montomoli
  • Journal Article
  • 2018-01-1105
Published 2018-04-03 by SAE International in United States
This article presents strategies for evaluating the mean, variance, and failure probability of a response variable given measurements subject to both epistemic and aleatory uncertainties. We focus on a case in which standard sensor calibration techniques cannot be used to eliminate measurement error since the uncertainties affecting the metrology system depend upon the measurement itself (e.g., the sensor bias is not constant and the measurement noise is colored). To this end, we first characterize all possible realizations of the true response that might have led to each of such measurements. This process yields a surrogate of the data for the unobservable true response taking the form of a random variable. Each of these variables, called a Random Datum Model (RDM), is manufactured according to a measurement and to the underlying structure of the uncertainty. Several random variable estimation and model calibration techniques are used within the RDM framework to approximate and bound the three metrics of interest. In contrast to all approximations, the bounding techniques account for the irreducible prediction error caused by the uncertainty.…
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Noise Control Capability of Structurally Integrated Resonator Arrays in a Foam-Treated Cylinder

SAE International Journal of Vehicle Dynamics, Stability, and NVH

NASA Langley Research Center-Albert Allen, Noah Schiller
Sandia National Laboratories-Jerry Rouse
  • Journal Article
  • 2017-01-1765
Published 2017-06-05 by SAE International in United States
Corrugated-core sandwich structures with integrated acoustic resonator arrays have been of recent interest for launch vehicle noise control applications. Previous tests and analyses have demonstrated the ability of this concept to increase sound absorption and reduce sound transmission at low frequencies. However, commercial aircraft manufacturers often require fibrous or foam blanket treatments for broadband noise control and thermal insulation. Consequently, it is of interest to further explore the noise control benefit and trade-offs of structurally integrated resonators when combined with various degrees of blanket noise treatment in an aircraft-representative cylindrical fuselage system.In this study, numerical models were developed to predict the effect of broadband and multi-tone structurally integrated resonator arrays on the interior noise level of cylindrical vibroacoustic systems. Foam layers with a range of thicknesses were applied near the inside surface of the cylinder to represent different degrees of conventional blanket treatments. Excitations including point force as well as harmonic and random fluctuating pressure fields were considered. The results suggest that structurally integrated resonators can be tuned to address a variety of noise control…
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Assessing Biofidelity of the Test Device for Human Occupant Restraint (THOR) Against Historic Human Volunteer Data

NASA Langley Research Center-Justin Littell
NASA Johnson Space Center-Michael Gernhardt
Published 2013-11-11 by The Stapp Association in United States
The National Aeronautics and Space Administration (NASA) is interested in characterizing the responses of THOR (test device for human occupant restraint) anthropometric test device (ATD) to representative loading acceleration pulse s. Test conditions were selected both for their applicability to anticipated NASA landing scenarios, and for comparison to human volunteer data previously collected by the United States Air Force (USAF).THOR impact testing was conducted in the fore-to-aft frontal (-x) and in the upward spinal (-z) directions with peak sled accelerations ranging from 8 to 12 G and rise times of 40, 70, and 100ms. Each test condition was paired with historical huma n data sets under similar test conditions that were also conducted on the Horizontal Impulse Accelerator (HIA). A correlation score was calculated for each THOR to human comparison using CORA (CORrelation and Analysis) software. A two -parameter beta distribution model fit was obtained for each dependent variable using maximum likelihood estimation.For frontal impacts, the THOR head x-acceleration peak response correlated with the human response at 8 and 10G 100ms, but not 10G 70ms.…
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NASA's Fundamental Aeronautics Subsonic Fixed Wing Project: Generation N+3 Technology Portfolio

NASA Langley Research Center-Richard Wahls
NASA Ames Research Center-Nateri Madavan
Published 2011-10-18 by SAE International in United States
Commercial aviation relies almost entirely on subsonic fixed wing aircraft to constantly move people and goods from one place to another across the globe. While air travel is an effective means of transportation providing an unmatched combination of speed and range, future subsonic aircraft must improve substantially to meet efficiency and environmental targets.The NASA Fundamental Aeronautics Subsonic Fixed Wing (SFW) Project addresses the comprehensive challenge of enabling revolutionary energy-efficiency improvements in subsonic transport aircraft combined with dramatic reductions in harmful emissions and perceived noise to facilitate sustained growth of the air transportation system. Advanced technologies, and the development of unconventional aircraft systems, offer the potential to achieve these improvements. Multidisciplinary advances are required in aerodynamic efficiency to reduce drag, structural efficiency to reduce aircraft empty weight, and propulsive and thermal efficiency to reduce thrust-specific energy consumption (TSEC) for overall system benefit. Additional advances are required to reduce perceived noise without adversely affecting drag, weight, or TSEC, and to reduce harmful emissions without adversely affecting energy efficiency or noise.The primary focus of the SFW Project is…
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Nowcasting Aircraft Icing Conditions in the Presence of Multilayered Clouds Using Meteorological Satellite Data

NASA Langley Research Center-Patrick Minnis, William Smith
Science Systems & Applications Inc-Fu-Lung Chang
Published 2011-06-13 by SAE International in United States
Cloud properties retrieved from satellite data are used to diagnose aircraft icing threat in single layer and multilayered ice-over-liquid clouds. The algorithms are being applied in real time to the Geostationary Operational Environmental Satellite (GOES) data over the CONUS with multilayer data available over the eastern CONUS. METEOSAT data are also used to retrieve icing conditions over western Europe. The icing algorithm's methodology and validation are discussed along with future enhancements and plans. The icing risk product is available in image and digital formats on NASA Langley ‘s Cloud and Radiation Products web site, http://www-angler.larc.nasa.gov.
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Aerodynamic Effects of Simulated Ice Accretion on a Generic Transport Model

NASA Langley Research Center-Gautam H. Shah, Patrick C. Murphy
ASRC Aerospace Corporation-Sam Lee
Published 2011-06-13 by SAE International in United States
An experimental research effort was begun to develop a database of airplane aerodynamic characteristics with simulated ice accretion over a large range of incidence and sideslip angles. Wind-tunnel testing was performed at the NASA Langley 12-ft Low-Speed Wind Tunnel using a 3.5% scale model of the NASA Langley Generic Transport Model. Aerodynamic data were acquired from a six-component force and moment balance in static-model sweeps from α = -5 to 85 deg. and β = -45 to 45 deg. at a Reynolds number of 0.24x10⁶ and Mach number of 0.06. The 3.5% scale GTM was tested in both the clean configuration and with full-span artificial ice shapes attached to the leading edges of the wing, horizontal and vertical tail. Aerodynamic results for the clean airplane configuration compared favorably with similar experiments carried out on a 5.5% scale GTM. The addition of the large, glaze-horn-type ice shapes did result in an increase in airplane drag coefficient but had little effect on the lift and pitching moment. The lateral-directional characteristics showed mixed results with a small effect…
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Neutron Transport Models and Methods for HZETRN and Coupling to Low Energy Light Ion Transport

SAE International Journal of Aerospace

NASA Langley Research Center-S. R. Blattnig
Old Dominion University-T. C. Slaba, J. H. Heinbockel
  • Journal Article
  • 2008-01-2162
Published 2008-06-29 by SAE International in United States
Exposure estimates inside space vehicles, surface habitats, and high altitude aircraft exposed to space radiation are highly influenced by secondary neutron production. The deterministic transport code HZETRN has been identified as a reliable and efficient tool for such studies, but improvements to the underlying transport models and numerical methods are still necessary. In this paper, the forward-backward (FB) and directionally coupled forward-backward (DC) neutron transport models are derived, numerical methods for the FB model are reviewed, and a computationally efficient numerical solution is presented for the DC model. Both models are compared to the Monte Carlo codes HETC-HEDS and FLUKA, and the DC model is shown to agree closely with the Monte Carlo results. Finally, it is found in the development of either model that the decoupling of low energy neutrons from the light ion (A≤4) transport procedure adversely affects low energy light ion fluence spectra and exposure quantities. A first order correction is presented to resolve the problem, and it is shown to be both accurate and efficient.
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