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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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At least 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Deny-by-Default Network Port Security: SPaRC Technical Bulletin #002

Operational Technology (OT) networks [e.g., industrial control systems (ICS) and supervisory control and data acquisition (SCADA) systems] have unique cyber security challenges due to their decades long service life, high availability requirements, and limited visibility. OT networks often take credit for being “air gapped” (i.e. disconnected from the Internet) and all devices within the OT network can “talk” to each other—even if they should not. This SPaRC Technical Bulletin describes how the unique limitations of OT networks can become strengths when it comes to cybersecurity.

Cybersecurity↗
DOE OSTI2022

Underwater Noise Measurements around a Tidal Turbine in a Busy Port Setting

Acoustic emissions from current energy converters remain an environmental concern for regulators because of their potential effects on marine life and uncertainties about their effects stemming from a lack of sufficient observational data. Several recent opportunities to characterize tidal turbine sound emissions have begun to fill knowledge gaps and provide a context for future device deployments. In July 2021, a commercial-off-the-shelf hydrophone was deployed in a free-drifting configuration to measure underwater acoustic emissions and characterize a 25 kW-rated tidal turbine at the University of New Hampshire’s Living Bridge Project in Portsmouth, New Hampshire. Sampling methods and analysis were performed in alignment with the recently published IEC 62600-40 Technical Specification for acoustic characterization of marine energy converters. Results from this study indicate acoustic emissions from the turbine were below ambient sound levels and therefore did not have a significant impact on the underwater noise levels of the project site. As a component of Pacific Northwest National Laboratory’s Triton Field Trials (TFiT) described in this Special Issue, this effort provides a valuable use case for the IEC 62600-40 Technical Specification framework and further recommendations for cost-effective technologies and methods for measuring underwater noise at future current energy converter project sites.

tidal turbine↗
DOE OSTI2015

Used-Oil Generation and Its Disposal along East-West Road, Port Harcourt Nigeria

Environmental Pollution from anthropogenic activities has contributed greatly towards the loss of biodiversity, and some organisms are at the verge of extinction and total extermination. Used oil as one of the wastes from automobile engines have contribute immensely towards the degradation of the environment and the problem of this has been traced to the poor handling of used oil and the ignorance of the major disposers of this used-oil. Out of 20 automobile mechanics interviewed in this study, 60% admitted that they dispose of used-oil on the land, 30% said that they sell it and only 10% acknowledge that they reuse it. On the issue of awareness about recycling, 50% admitted that they are aware, 30% claimed ignorance while 20% do not see the need for recycling. While considering storage method, 55% said that they do not store used oil, 25% store it in a metal drum, and 20% store in plastic drum. The mechanics estimated that about 418 cars are serviced weekly and a total of 1628.50 litres of used-oil are produced. For this result it is worth knowing that indiscriminate disposal of used oil as is commonly observed in our society can be of great environmental concern.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Potential Impacts of High-Octane Fuel Introduction in a Naturally Aspirated, Port Fuel-Injected Legacy Vehicle

In recent years there has been an increased interest in raising the octane level of gasoline to enable higher compression ratios (CR) in spark-ignition engines to improve vehicle fuel efficiency. A number of studies have examined opportunities to increase efficiency in future vehicles, but potential impacts on the legacy fleet have not received as much attention. In this study, our effort focused on experimental studies on an engine using high-octane fuels without changing the engine’s CR. Spark timing was advanced until maximum torque was reached or knock was encountered for each engine condition, using each individual fuel to maximize engine efficiency. Knock-limited conditions occurred as the output brake mean effective pressure (BMEP) neared the maximum attainable output at a given engine speed. Increasing research octane numbers generally enabled knock-free operation under a greater number of operating conditions. Vehicle modeling using Autonomie was used to project vehicle energy use, fuel economy, and tailpipe CO 2 emissions for the Urban Dynamometer Driving Schedule (UDDS), the Highway Fuel Economy Test (HWFET), and the US06 cycle. Results show that decreases in energy consumption of up to 2% for a small SUV are possible through the use of a 97 RON fuel compared to a baseline using 91 RON fuel, provided that the formulation of the fuel does not cause unanticipated operational issues such as lower maximum BMEP. Greater improvements using high-octane fuels are possible if the CR is increased, but there is no opportunity to increase the CR in legacy vehicles. Thus, these vehicles realize an improvement from increased octane rating in accordance with their ability to spark advance to take advantage of a fuel with a higher octane rating. For the modeled vehicle, improvements of up to 2% in volumetric fuel economy may be possible through the use of a 97 RON fuel with the largest gains expected on the US06 cycle. Fuel economy impacts are strongly coupled to the heating value of the fuels in addition to changes in engine efficiency. Similarly, decreases in tailpipe CO 2 emissions are also achievable. However, simultaneous improvements in energy consumption, fuel economy, and tailpipe CO 2 emissions are not guaranteed and are dependent upon fuel formulation.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2023

Porting the WAVEWATCH III (v6.07) wave action source terms to GPU

Abstract. Surface gravity waves play a critical role in several processes, including mixing, coastal inundation, and surface fluxes. Despite the growing literature on the importance of ocean surface waves, wind–wave processes have traditionally been excluded from Earth system models (ESMs) due to the high computational costs of running spectral wave models. The development of the Next Generation Ocean Model for the DOE’s (Department of Energy) E3SM (Energy Exascale Earth System Model) Project partly focuses on the inclusion of a wave model, WAVEWATCH III (WW3), into E3SM. WW3, which was originally developed for operational wave forecasting, needs to be computationally less expensive before it can be integrated into ESMs. To accomplish this, we take advantage of heterogeneous architectures at DOE leadership computing facilities and the increasing computing power of general-purpose graphics processing units (GPUs). This paper identifies the wave action source terms, W3SRCEMD, as the most computationally intensive module in WW3 and then accelerates them via GPU. Our experiments on two computing platforms, Kodiak (P100 GPU and Intel(R) Xeon(R) central processing unit, CPU, E5-2695 v4) and Summit (V100 GPU and IBM POWER9 CPU) show respective average speedups of 2× and 4× when mapping one Message Passing Interface (MPI) per GPU. An average speedup of 1.4× was achieved using all 42 CPU cores and 6 GPUs on a Summit node (with 7 MPI ranks per GPU). However, the GPU speedup over the 42 CPU cores remains relatively unchanged (∼ 1.3×) even when using 4 MPI ranks per GPU (24 ranks in total) and 3 MPI ranks per GPU (18 ranks in total). This corresponds to a 35 %–40 % decrease in both simulation time and usage of resources. Due to too many local scalars and arrays in the W3SRCEMD subroutine and the huge WW3 memory requirement, GPU performance is currently limited by the data transfer bandwidth between the CPU and the GPU. Ideally, OpenACC routine directives could be used to further improve performance. However, W3SRCEMD would require significant code refactoring to make this possible. We also discuss how the trade-off between the occupancy, register, and latency affects the GPU performance of WW3.

58 GEOSCIENCES↗
NASA NTRS1972

An investigation of rooftop STOL port aerodynamics

An investigation into aerodynamic problems associated with large building rooftop STOLports was performed. Initially, a qualitative flow visualization study indicated two essential problems: (1) the establishment of smooth, steady, attached flow over the rooftop, and (2) the generation of acceptable crosswind profile once (1) has been achieved. This study indicated that (1) could be achieved by attaching circular-arc rounded edge extensions to the upper edges of the building and that crosswind profiles could be modified by the addition of porous vertical fences to the lateral edges of the rooftop. Important fence parameters associated with crosswind alteration were found to be solidity, fence element number and spacing. Large scale building induced velocity fluctuations were discovered for most configurations tested and a possible explanation for their occurrence was postulated. Finally, a simple equation relating fence solidity to the resulting velocity profile was developed and tested for non-uniform single element fences with 30 percent maximum solidity.

Blanton, J. N.↗
NASA NTRS1975

Airloads near the open port of a one-meter airborne telescope

An infrared telescope is mounted in a cavity in the fuselage of a C-141 airplane. The cavity is sealed off from the rest of the fuselage and can be opened to the outside for viewing. A retractable porous spoiler is installed ahead of the opening to inhibit cavity resonance. The paper presents the mean pressures, pressure fluctuations, spectra, phase, and coherence of the pressures in the cavity and on the fuselage near the cavity, along with pertinent acceleration and torque information for the aircraft structure and telescope. It is shown that a moderate spoiler extension controls resonance in normal flight attitudes and produces a cavity environment with approximately the same turbulence intensity as an attached turbulent boundary layer.

Buell, D. A.↗
NASA NTRS1980

Reduction of unsteady wind torques on an open port airborne optical turret

Techniques for reducing the unsteady torques acting on the inner gimbal of a turret were developed. The reductions in the unsteady torques were obtained by using fixes that alter undesirable flow characteristics or change the acoustic properties of the turret cavity. These fixes were designed to be used in the subsonic and transonic flow regimes. The flow field about the turret generally three dimensional and turbulent, and shock waves formed because of the rapid acceleration of the compressible gas about the blunt turret. The situation was further complicated by the presence of the cavity flow, and the fact that the mouth of the cavity must sweep through a wide angular variation relative to the direction of the freestream. Results indicate that significant reductions of the unsteady pressures measured in the turret cavity could be obtained by the use of porous wind screens around the aperature of the cavity mouth.

Thomas, J. P., Jr.↗
NASA NTRS1980

A study of optimum cowl shapes and flow port locations for minimum drag with effective engine cooling, volume 1

The contributions to the cruise drag of light aircraft arising from the shape of the engine cowl and the forward fuselage area and also that resulting from the cooling air mass flow through intake and exhaust sites on the nacelle were analyzed. The methods employed for the calculation of the potential flow about an arbitrary three dimensional body are described with modifications to include the effects of boundary layer displacement thickness, a nonuniform onset flow field (such as that due to a rotating propeller), and the presence of air intakes and exhausts. A simple, reliable, largely automated scheme to better define or change the shape of a body is also presented. A technique was developed which can yield physically acceptable skin friction and pressure drag coefficients for isolated light aircraft bodies. For test cases on a blunt nose Cessna 182 fuselage, the technique predicted drag reductions as much as 28.5% by body recontouring and proper placements and sizing of the cooling air intakes and exhausts.

Fox, S. R.↗