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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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DGEN Aeropropulsion Research Turbofan (DART) Core/Combustor-Noise Infinite-Tube-Probe (ITP) Transfer Function
Direct measurements of turbofan engine core unsteady pressure is complicated by the extreme thermal environment within the engine, preventing currently available transducers from operating. It is necessary to use a remote measurement configuration such as an infinite-tube-probe (ITP) configuration in which the transducer is teed into a line pneumatically coupled with the location of interest and the other end of the ITP contains an "infinite" waveguide designed to prevent any reflections. This configuration has become a standard method for experiments concerning core noise. In order to relate the spectral pressure measurements obtained remotely with the ITP, a transfer (frequency response) function needs to be calculated based on a known pressure field. This is accomplished using a normal impedance tube at Glenn Research Center, where a flush-mounted microphone is used as a reference to the ITP signal in the calculation of the ITP's transfer function.
Fate and Dynamics of Ejecta Liberated by the Proposed DART Impact
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Radio Science and Measuring DART-Induced Deflection with Observer Spacecraft
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Planetary Defense Missions Post-DART/NEOSM
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Dynamics of ejecta plume after the DART impact on Dimorphos
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Distributed Aperture Radar Tomographic Sensors (DARTS) to Map Surface Topography and Vegetation Structure
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Improving the Representation of Land Surface Processes Using the Data Assimilation Research Testbed (DART)
The land surface is a critical part of the earth system as processes related to water, carbon, energy and nitrogen cycling have important implications for climate forcing, air quality, water availability and seasonal atmospheric forecasting. Despite advances in land surface modeling, land surface model performance is often limited because of errors related to initial and boundary conditions, model structure, and parameters. Data assimilation (DA) techniques combined with an expanding network of earth system observations present an opportunity to reduce these errors and improve simulations. Here, we emphasize the implementation of tools and approaches to overcome challenges related to land DA to constrain carbon and water cycling. In particular, we discuss the implementation of adaptive inflation to modify ensemble spread in response to time-varying networks of gridded observations. We also discuss methods to generate ensemble spread through boundary condition (meteorology) forcing that can be applied to site-level applications. Next, we describe the application of vertical localization upon surface soil moisture observations, and forward operators specifically designed for the assimilation of snow and solar-induced fluorescence observations. Finally, we discuss the potential benefit of a quantile conserving filter used to update bounded quantities (state or parameter values).
Predicting Asteroid Material Properties from a DART-like Kinetic Impact
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“Chaotic” dart leaders in triggered lightning: Electric fields, X‐rays, and source locations
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Assessing the impacts of assimilating IASI and MOPITT CO retrievals using CESM‐CAM‐chem and DART
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The Relative Effects of Surface and Subsurface Morphology on the Deflection Efficiency of Kinetic Impactors: Implications for the DART Mission
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