The new Graphical User-Interface (GUI) has been in the field for some months. Thanks to users feedback several improvements and bug fixes could be implemented.
The Friedlander blast-wave model (“TNTAir”) offered as an option within the Off-site-blast functionality has been improved: the correlations for peak overpressure, positive duration, wave-shape (factor in the exponential term) and time of arrival have been revised to better match the APOLLO predictions for airblast waves. Particularly the modelling of the negative phase has been improved, which suffered from insufficient accuracy before. As a result, the perturbations generated at feed-in boundaries due to discrepancies between APOLLO predictions and the Friedlander model were (in most cases) reduced.
An alternative EOS parameter set for Air is offered in apollo-eos.dat (“Air2”), which provides an improved sound speed value at ambient state. This model is recommended to be used with the TNTAir model in Off-Site-Blast.
The numerical methods applied for the simulation of jet blow-down have been revised and improved, leading to better comparisons with available test data.
A new output file NAME_eos is now generated when a non-default version of apollo-eos.dat is used in a simulation (see section EOSFILE). This file saves a copy of the parameter sets loaded from the selected apollo-eos.dat file. Thereby the parameter values actually used for a simulation are documented together with the simulation results and can be looked up, even if changes have been made in the apollo-eos.dat file.
A new, extended version of the KAB model (KABX) has been implemented which covers both gaseous afterburning and the finite rate particle combustion which occurs in metallized explosives. The model has recently been successfully calibrated and applied for an aluminized explosive (not included in apollo-eos.dat). A calibration of the KABX model for TNT (w/o the optional particle combustion) is included in apollo-eos.dat. Tests with that model have shown improved accuracy compared to the original KAB model.
An error in the implementation of the original KAB model in the 2023 versions has been found and corrected. Due to a miscalculation of the fireball volumes in these versions, the afterburning may have been underestimated in these versions. This has been corrected in the current version.
The keyword “Charge” for the respective option of the zoom-functionality has been changed into “Charge-Airblast” to make clear that the settings selected thereby are tuned for explosions in air. For the same reason the meshing option “Auto” in DOMAIN-B1D has been renamed to “Auto-Airblast”. In the next update complementary settings for UNDEX will be implemented.
Initiation positions Tail, Head and Booster selectable in CHARGES are automatically shifted about a small length into the charge to ensure successful initiation. While a fraction of charge length was used for this shift before, this has been changed to a fraction of a grid cell now.
A new Graphical User-Interface (GUI) is ready. The GUI allows you to set-up the input file for the APOLLO Blastsimulator. You can launch a simulation and monitor its progress as the GUI displays the continuously updated log-file content and diagrams of all generated history files.
The GUI writes and reads input files – that means you can also edit the input file outside the GUI (e.g. to import gauge positions from another data source) and reload it into the GUI.
The GUI is presently available for Windows only and released in a beta-mode. Please use it tentatively and give us a feed-back and report problems. Your participation in this matter is appreciated.
The specification of fluids, particles and reactions in FLUIDS and PARTICLES is now in terms of names rather than key-numbers. While hitherto the key numbers in apollo-eos.dat had to be unique, they can now be used repeatedly. Thereby the addition of variants of the same material is simplified which can all use the same key number now.
As a new feature the input file now optionally includes a section EOSFILE. Here you can specify a path/name to the eos-file that should be used for the simulation (and in the GUI) other than the default file apollo-eos.dat provided in /exe. This new feature simplifies working with modifications of EOS parameter values or addition of new material variants. A modified EOS file can e.g. be located in a project folder. If EOSFILE is used, an additional outputfile NAME_mat is produced, where the data loaded from the selected eos-file is documented; thereby the parameter values used in a run can be retrieved, even if the contents of the eos-file was modified at a later time.
A model has been implemented for the coefficient of restitution, which governs the mechanical interaction of particles with wall boundaries or embedded objects. The coefficient depends on particle velocity and temperature and is parameterized by yield strength, Youngs modulus and friction coefficient. The input of these parameter values replaces the input of a static coefficient of restitution for particle materials in Apollo-eos.dat.
The definition of particle materials and particle reactions hitherto used a hard-wired reference diameter (1 μm) for ignition criteria and burn times. The reference diameter can now be chosen arbitrarily. The Apollo-eos.dat file supplied with the new version has been modified according to these changes.
Download PDF or consult the manual to get the full list of changes.
