Software

Computational Model of a Plasma Actuator

Controlling subsonic aerodynamic flow through the use of plasma actuators is an active area of research in both the Air Force (AF) and the general scientific community. A typical plasma actuator consists of two offset electrodes separated by a dielectric material (see Figure 1). Plasma forms as the voltage difference between the electrodes ionizes the surrounding gas. The electric field can then direct the charged particles in the plasma to transfer momentum to the surrounding, neutral (nonionized) air. Most of this momentum transfer occurs as a result of particle collisions. Experiments have demonstrated the ability of plasma actuators to reattach separated airflow at high angles of attack (see Figure 2), as well as to induce flow movement in an initially stationary air mass.1,2,3,4,5

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Unified Flow Solver

A variety of gas flow problems are characterized by the presence of rarefied and continuum domains. In a rarefied domain, the mean free path of gas molecules is comparable to (or larger than) a characteristic scale of the system. The rarefied domains are best described by particle models such as Direct Simulation Monte Carlo (DSMC); or, they involve solution of the Boltzmann kinetic equation for the particle distribution function. The continuum flows are best described by Euler or Navier-Stokes equations in terms of average flow velocity, gas density, and temperature and are solved by computational fluid dynamics (CFD) codes. The development of hybrid solvers combining kinetic and continuum models has been an important area of research over the last decade. Potential applications of such solvers range from high-altitude flight to gas flow in microsystems.

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Geo*View

Visualization of geospatially correct, remotely sensed data is a key element of many government and commercial applications. It enables a user to analyze and assess ground activities and other conditions of interest. Because remotely sensed data can include a diversity of data types reflecting many different data formats, users may experience difficulty visualizing and interpreting these varying data types and formats due to data structure complexity. In addition, important supplemental information often accompanies the data. This supplemental information—or metadata— may include pertinent information of significant value to the user with respect to where, when, and how data collection occurred. Whereas some applications require metadata to support geospatial analysis functions such as positioning and measurement, many others are unable to interpret such metadata and it may thus go unnoticed. Multiband data and motion imagery further compound the task of visualization with spectral components and complex video streams interlaced with other geospatial information.

Posted in: Briefs, Software, Data acquisition and handling, Imaging
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A Software Development Process for Small-Scale Embedded Systems

Developing software for small-scale embedded applications is different from developing large-scale software applications. Large-scale applications use commercially available ‘one fits all’ software development solutions that are difficult to scale downward and usually miss the desired process goals. In many cases, developing a small-scale software application development process within an existing corporate environment is quicker, less expensive, and results in superior developer productivity and product quality.

Posted in: Articles, Articles, Embedded Technology, Board-Level Electronics, Electronics & Computers, Software, Embedded software, Product development
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