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, Aircraft

Towed Airborne Plume Simulator

Arnold Engineering Development Complex
Arnold Air Force Base, TN
For more info click here

A team of engineers at AEDC are supporting the continued development and testing of the Towed Airborne Plume Simulator (TAPS), a simulator that can be towed behind aircraft for testing missile warning and infrared countermeasure systems. Most recently the AEDC TAPS team assisted the Air Force Research Laboratory with a mission in Australia.

Posted in: Application Briefs, Aerospace, Defense, Simulation and modeling, Exhaust emissions, Aircraft operations, Test equipment and instrumentation

3D Printed Primary Flight Control Component

Liebherr-Aerospace & Transportation SAS
Toulouse, France
+49 8381 46 4403
For more info click here

Airbus recently successfully flew Liebherr-Aerospace's 3D printed spoiler actuator valve block on a flight test A380. It was the first 3D printed primary flight control hydraulic component flown on an Airbus aircraft.

Posted in: Application Briefs, Aerospace, Defense, Flight control actuators, Suppliers, Additive manufacturing, Parts

F-16 Upgrades

Lockheed Martin
Bethesda, MD
For more info click here

The U.S. Air Force recently authorized extending the service life of the Lockheed Martin F-16's designed service life to 12,000 Equivalent Flight Hours — far beyond the aircraft's original design service life of 8,000 hours.

Posted in: Application Briefs, Aerospace, Defense, Suppliers, Military aircraft

NeXtRAD SDR Interface

Pentek, Inc.
Upper Saddle River, NJ
For more info click here

NeXtRAD is a dual-band, dual-polarization, multistatic radar system under development at the University of Cape Town (UCT) in collaboration with University College London (UCL). The primary mission of the system is to collect multistatic data of small radar cross-section maritime targets embedded in sea clutter.

Posted in: Application Briefs, Aerospace, Defense, Radar, Suppliers

Measuring Propellant Stress Relaxation Modulus Using Dynamic Mechanical Analyzer

Structural analysis of solid rocket motors is challenging for several reasons, but the most important of these is the complex behavior of the propellant. The mechanical response of a solid propellant is time and temperature dependent. The complexity of the mathematical analysis of the propellant depends on the loading conditions, but for some loading situations, the linear viscoelasticity assumption is reasonable. In particular, linear viscoelasticity is perhaps the most appropriate material behavior description for use in the simulations of stresses related to storage conditions. Typically, simulations use a viscoelastic model in the form of a Prony series and a Williams–Landel–Ferry (WLF) equation. The parameters in these models are derived from stress relaxation experiments, making the stress relaxation experiment a key viscoelastic test, analogous to the tensile test for linear elastic materials.

Posted in: Briefs, Aerospace, Defense, Fluid Handling, Propulsion, Solid propellants, Spacecraft fuel, Performance tests

Combustion Characteristics of Hydrocarbon Droplets Induced by Photoignition of Aluminum Nanoparticles

In the study of combustion characteristics of liquid rocket fuels, it is customary to either study the combustion of liquid fuel droplets or the combustion of fuel sprays. However, the two are closely related to each other, because in a typical rocket combustion chamber, the burning of droplets, droplet clusters, and fuel sprays occur simultaneously.

Posted in: Briefs, Aerospace, Defense, Propulsion, Test & Measurement, Spacecraft fuel, Aluminum, Combustion and combustion processes, Liquid propellant rocket engines

Vapor Pressure Data and Analysis for Selected Organophosphorous Compounds: DIBMP, DCMP, IMMP, IMPA, EMPA, and MPFA

Knowledge of the physical properties of materials is critical for understanding their behavior in the environment as well as in the laboratory. Vapor pressure is an important physical property for a wide variety of chemical defense-related applications, including estimation of persistence, prediction of downwind time-concentration profiles after dissemination, generation of controlled challenge concentrations for detector testing, evaluation of toxicological properties, and assessment of the efficiency of air filtration systems.

Posted in: Briefs, Aerospace, Defense, Emergency management, Chemicals, Materials properties, Hazardous materials

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

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, Aerospace, Defense, Computational fluid dynamics, Marine vehicles and equipment

Assessment of Non-Traditional Isotopic Ratios by Mass Spectrometry for Analysis of Nuclear Activities

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, Aerospace, Defense, Nuclear energy, Identification, Test procedures