Tech Briefs

Predictive Computations of Single-Phase Turbulent Flows

Explicitly filtered large-eddy simulation is used. NASA’s Jet Propulsion Laboratory, Pasadena, California This software computes a single-phase turbulent flow. The solution is independent of the grid spacing on which it is computed, and on the discretization order used for the differential equations. Grid spacing and discretization-order independence can be achieved by reformulating the large-eddy simulation (LES) equations. Previous software followed the conventional LES equations, whereas the present one follows the explicitly filtered formulation (EFLES).

Posted in: Briefs, Simulation Software

Read More >>

Predictive Computation of Two-Phase Turbulent Flows with Phase Change

Explicitly filtered large-eddy simulation is used. This software computes two-phase turbulent flows with phase change, and the solution is independent of the grid spacing on which it is computed and on the discretization order used for the differential equations. Grid spacing and discretization-order independence can be achieved by reformulating the large-eddy simulation (LES) equations. Previous software followed the conventional LES equations, whereas the present one follows the explicitly filtered formulation (EFLES).

Posted in: Briefs, Simulation Software

Read More >>

Physics-Model-Based Wiring Fault Detection Toolbox for MATLAB

Ames Research Center, Moffett Field, California This software provides a toolbox of MATLAB functions for detecting precursor wiring faults, such as chafing, in shielded impedance-controlled cable using measurements from off-the-shelf time domain reflectometry or vector network analyzer hardware. It advances the state-of-the-art in wiring fault detection, currently limited to the detection of hard opens or shorts, by combining high-fidelity analytical physics models for signal propagation on faulty cable with fast Bayesian inference algorithms for intrinsic cable and fault parameter retrieval. The overall approach is robust to noisy operating conditions, and does not require fixed baseline measurements. More information about this software can be found at: http://ti.arc.nasa.gov/project/wiring.

Posted in: Briefs

Read More >>

PEGASUS 5.2: Automated Pre-Processing of Overset CFD Grids

Ames Research Center, Moffett Field, California The Pegasus software is used as a pre-processor for overset-grid computational fluid dynamic (CFD) simulations. The main features of the software include: automated hole cutting algorithms; a projection scheme for fixing small discretization errors in overset surfaces; efficient interpolation search methods; hole-size optimization based on adding additional layers of fringe points; and an automatic restart capability. The code can be run in parallel using the Message-Passing Interface standard. The parallelization performance provides efficient speed-up of the execution time capable of utilizing dozens or even hundreds of processors.

Posted in: Briefs, Simulation Software

Read More >>

ACES ToolSuite

Langley Research Center, Hampton, Virginia The NASA Langley Aeronautics Systems Analysis Branch (ASAB) is heavily involved in research studies to evaluate new and emerging concepts targeted at improving the National Airspace System (NAS). The primary tool used by ASAB to perform these studies is the Airspace Concept Evaluation System (ACES), a medium-fidelity, NAS-wide simulation environment.

Posted in: Briefs, TSP, Electronics & Computers, Simulation Software

Read More >>

Modeling for Partitioned and Multicore Flight Software Systems

NASA’s Jet Propulsion Laboratory, Pasadena, California The current flight software approach is monolithic in nature. Every module has tentacles that reach deep within dozens of other software modules. Because of these interdependencies between modules, functionality is difficult to extract and reuse for other missions.

Posted in: Briefs, TSP, Aviation, Electronics & Computers

Read More >>

ATLAS Collaborative Spacecraft and Mission Software Design Tool

Ames Research Center, Moffett Field, California This software conducts preliminary design studies for spacecraft missions. It supports a collaborative work environment that allows multiple engineers to work simultaneously on the same design. When designing a spacecraft or mission, it is important that each engineer has concurrent data information to ensure consistency in the overall design. However, the complex nature of different subsystems poses a unique problem, because certain inputs require outputs from different subsystems, and all data must be current in order to reach a systematic solution. With ATLAS, when a design is adjusted based on analysis results, new design parameters can be seen by all other clients. Various existing commercial software tools perform similar functions, but none are known to be specifically tailored toward collaborative design of spacecraft missions. ATLAS provides analysis tools with a shared data environment supporting shared work.

Posted in: Briefs, Computer-Aided Design (CAD)

Read More >>