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Coupling of Coastal Wave Transformation and Computational Fluid Dynamics Models for Seakeeping Analysis

New analytical tools improve understanding of vessel operating environments in the littorals.

This research focused on depth-integrated modeling of coastal wave and surf-zone processes in support of computational fluid dynamics (CFD) simulation of ship motions. There were two components of the project. The first was the development of a numerical dispersion relation for a family of Boussinesq-type equations commonly used in modeling of coastal wave transformation. The relation depicts numerical dissipation and dispersion in wave propagation and provides guidelines for model setup in terms of temporal and spatial discretization. The second component was an extension of existing depth-integrated wave models to describe overtopping of coastal reefs and structures along with a series of CFD and laboratory experiments for model validation. The basic approach utilizing the HLLS Riemann solver performs reasonably well and produces stable and efficient numerical results for practical application.

Posted in: Briefs, TSP, Aerospace, Defense, Computational fluid dynamics, Marine vehicles and equipment
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Assessment of Non-Traditional Isotopic Ratios by Mass Spectrometry for Analysis of Nuclear Activities

Technique can be used to distinguish between commercial nuclear reactor fuel cycles, fuel cycles for weapons grade plutonium, and products from nuclear weapons explosions.

The objective of this work is to identify isotopic ratios suitable for analysis via mass spectrometry that distinguish between commercial nuclear reactor fuel cycles, fuel cycles for weapons grade plutonium, and products from nuclear weapons explosions. Methods will also be determined to distinguish the above from medical and industrial radionuclide sources.

Posted in: Briefs, TSP, Aerospace, Defense, Nuclear energy, Identification, Test procedures
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The Rapid Rise of Beryllium-Aluminum Alloys in Aerospace

Enhanced performance operating envelopes for aerospace platforms continue to challenge industry limits. Aerospace platform operators demand extreme performance in harsh environments from the aircraft, UAVs, and satellites they deploy today: lighter weight, greater strength, superior fuel efficiency and operational range, vibration-mitigated platforms, low coefficients of thermal expansion, better corrosion resistance — the list goes on.

Posted in: Articles, Aerospace, Defense, Aircraft structures, Aluminum alloys, Beryllium, Materials properties
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New Products: August 2017 Aerospace & Defense Technology

Rugged Data Recorders

DTS’ (Seal Beach, CA) ultra-small SLICE MICRO and NANO data recorders are rugged and designed to embed directly in the test article – even small drones. The NANO has a footprint of just 26 × 31 mm. The standalone systems include a microprocessor, excitation, full signal conditioning, and sample up to 500,000 sps/channel.

Posted in: Products, Aerospace, Defense
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Aeroacoustic Simulation Delivers Breakthroughs in Aircraft Noise Reduction

Aircraft manufacturers face increasingly stringent standards for reducing community noise. Conventional aircraft development methods based on engineering experience, past designs and flight testing will not suffice to meet future noise reduction targets. Computational Fluid Dynamics (CFD) software based on so-called Reynolds-averaged Navier-Stokes (RANS) methods has revolutionized aerodynamics engineering, but is insufficient for high-fidelity aeroacoustic simulation. However, the Lattice-Boltzmann-based technology of Exa Corporation’s PowerFLOW software provides aeroacoustic simulation accuracy comparable to wind tunnels and flight testing.

Posted in: Articles, Aerospace, Defense, Computational fluid dynamics, Noise pollution, Acoustics, Acoustics, Aircraft
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Thermoelectric Cooling: How Does It Work? Why Should You Choose It?

There are many places one can go to get an outline on the pros and cons of different methods for enclosure cooling. Although we will briefly touch on them here, this is really an in-depth article on how to choose a Peltier (thermoelectric) air conditioner, once you have committed to the technology.

Posted in: White Papers, White Papers, Electronics & Computers
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Sound-Off: How to Simulate the Impacts of an Exoskeleton

Over the past decade, warfighters’ personal loads have increased, leading to more injuries, pain, and discomfort. To relieve the burden, the military is investigating performance-enhancing exoskeletons. But how does an exoskeleton impact the soldier wearing it?

Posted in: News, News, Computer-Aided Design (CAD), Simulation Software, Software
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Army to Test-Fire Tactical Missile System

Field artillery soldiers will soon be ready to test-fire the modernized Army Tactical Missile System (ATACMS) at White Sands Missile Range, New Mexico. Bravo Battery, 2nd Battalion, 20th Field Artillery Regiment is undergoing intensive training on the latest versions of software before operational testing.

Posted in: News, Defense
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Researchers Achieve Breakthrough in Nuclear Threat Detection Science

Taking inspiration from an unusual source, a Sandia National Laboratories team has dramatically improved the science of scintillators — objects that detect nuclear threats. According to the team, using organic glass scintillators could soon make it even harder to smuggle nuclear materials through America’s ports and borders.

Posted in: News, Defense, Materials, Detectors
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Batteries That “Drink” Seawater Could Power Long-Range UUVs

The long range of airborne drones helps them perform critical tasks in the skies. Now MIT spinout Open Water Power (OWP) aims to greatly improve the range of unpiloted underwater vehicles (UUVs), helping them better perform in a range of applications under the sea.

Posted in: News, Defense, Energy Storage, Materials, Robotics
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