Synthetik Applied Technologies announces the latest release of blastFoam - a free and open-source CFD airblast code for modeling high-explosive detonations

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The Synthetik Applied Technologies team is excited to announce the release of blastFoam v3.0

Given the disruption to their planned software release schedule, and the growing user community who have used these extraordinary times to pick-up and start using the software, Synthetik has decided to advance the planned release date and have announced their most significant release to date, blastFoam v3.0.

blastFoam now includes thirteen equations of state that allow modeling of diverse materials under extreme conditions, with consideration of phenomenologies such as excitation, dissociation and ionization of nitrogen and oxygen in air at higher energies and temperatures, afterburn, and sympathetic detonation.

Several different approaches have been introduced to model detonation within explosive materials which transition from unreacted energetics to detonation products, including pressure-based activation models with multi-step Arrhenius reaction rates, and simple, yet practical models based on empirically derived detonation velocities. Users can also specify instantaneous activation.

blastFoam allows phenomena such as size effect (decrease of the detonation velocity with decreasing charge radius), and detonation front curvature (induced by edge lag of the front as energy is lost to the exterior of the charge) to be accurately captured. These additions greatly enhance timing accuracy and load characterization, especially for near-contact explosive scenarios. Options for modeling afterburn (i.e., under-oxygenated explosives continuing to burn after detonation) are also included using the Miller extension, constant, and linear rate models.

blastFoam extends OpenFOAM’s base AMR library, and includes the ability to perform 2D and 3D adaptive mesh refinement (AMR). The refinement criteria can be based on density gradient, change across faces (delta), or Lohner’s method (2nd derivative of a field) to determine what cell should be refined or unrefined. Additionally, options for mesh unrefinement/relaxation/coarsening have been added, and this is useful for keeping cell counts relatively constant during a calculation while still capturing key features (e.g. shocks) with high accuracy. This allows blastFoam to solve engineering-scale simulations at an affordable computational cost.

blastFoam extends OpenFOAM by adding dynamic load rebalancing for adaptive grids, and now includes a working solution for 2D and experimental support for 3D calculations. Essentially, at a predetermined timestep interval the domain is rebalanced so that the cell count per CPU is more evenly distributed. This mitigates potential memory issues such as crashing and slow-down related to overloading CPUs that are operating on zones of high refinement.
Turbulence and radiation models have been integrated, allowing blastFoam users to leverage the extensive OpenFOAM libraries and apply them to their simulations, and a new fluid model structure (fluidThermo class), that extends OpenFOAM’s standard thermo classes has been added, and provides thermodynamically consistent solutions for more accurate temperature calculations.

New functionObjects have been added to improve usability, including the ability to calculate peak overpressure and impulse for each cell in the domain, as well as blastToVTK, a utility to view time series mesh surface outputs in ParaView.

Additional validation and tutorial cases are also provided to demonstrate and showcase the new functionality and capabilities of blastFoam v3.0.

Background:

The engineering community needs open, verifiable, validated blast and detonation simulation tools. Currently available tools: 1) are prohibitively expensive to license to run calculations at the scale and number of CPU cores and nodes required to capture key blast phenomena, 2) do not provide access to the underlying code due to concerns over intellectual property rights, 3) use non-universal file formats for pre- and post-processing, and 4) contain export controlled or distribution limited components. In response to these limitations, Synthetik Applied Technologies leveraged a widely used opensource CFD library as a foundation upon which to develop a new solver suited for high-explosive detonation modeling and simulation, blastFoam.

Synthetik’s solver builds upon the most widely utilized opensource CFD platform available today, and is currently deployed at DoD HPC Centers (e.g., AFRL, ARL, ERDC, Navy, ORS). The code contains multiple utilities to prepare calculations for complex geometries of interest (e.g. engineering-scale; from CAD models), including parallel mesh generation, mesh refinement, advanced post-processing, and import/export functions. Verification and validation studies have been conducted with independent validation (conducted by others) performed on larger-scale problems with complex geometries and published in peer-reviewed journals. The solver can be run on any modern platform (e.g. laptop, workstation, HPC, AWS, GCP, etc.).

Synthetik is a formal Texas Advanced Computing Center (TACC) Industry Partner, with access to High- Performance Computing (HPC) resources on systems such as the new NSF-funded petascale computing system, Frontera, thus allowing Synthetik to develop and test on state-of-the-art systems at scale.

About Synthetik Applied Technologies:

Synthetik Applied Technologies LLC is a fast-growing technology start-up that is creating breakthrough technology to mitigate the greatest threats to the world around us, including terrorism, extreme events and global environmental impact. Founded in 2017 and headquartered in Austin, Texas, Synthetik is already working with the U.S. Air Force, the Defense Advanced Research Projects Agency (DARPA), U.S. Department of Homeland Security (DHS), and the National Oceanic and Atmospheric Administration (NOAA) on highly innovative AI solutions. Synthetik also provides consulting services to the world’s largest insurance companies and maintains their state-of-art data analytics and scientific computing platforms including: cityCORE, blastKit, and a new U.S. Department of Defense-backed CFD solver for high-explosive detonation, blastFoam. Synthetik is an official partner of the Texas Advanced Computing Center (TACC) and the Microsoft AI for Earth program.

If you would like more information about this topic, please call Tim Brewer at (818) 296-8611, or email brewer@synthetik-technologies.com

Learn more:

Synthetik Applied Technologies: https://www.synthetik-technologies.com/

Free online blastFoam Workshop | May 13, 2020: https://www.eventbrite.com/e/blastfoam-workshop-tickets-100310659884

blastFoam is available for free download here: https://github.com/synthetik-technologies/blastfoam

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Tim Brewer
@synthetik_tech
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