After approximately nine months of work spent developing, testing, and validating, we are proud to announce that US3D-1.1.6 is now available for download from the VIrtusAero HTTPS and SFTP sites.  Additional details regarding this release can be found below.

Please note: We have updated both the password used to reach the download sites, and the GPG encryption / decryption key-pair.  If you need this updated access information, please email VirtusAero Support with your request.

Bugfixes and Improvements
A long list of bugfixes and improvements have been incorporated into the code since the US3D-1.1.1 release last year.  Internally we built and released versions 1.1.2 – 1.1.5 and performed extensive testing to ensure that US3D-1.1.6 is a stable patch release of US3D-1.1.  Highlights of improvements include:

• More accurate and consistent flux Jacobians should give improved convergence
• Fixed an issue with BC blending that caused a spike in residual on restarts
• Revised and improved reaction handler mechanism (for user reactions and plugins)
• Added Vreman algebraic subgrid-scale turbulence model and the BSL-V turbulence model
• Added additional scripting commands ‘cycle’ and ‘break’, and more conditional tests
• Added more observer method signals for triggering events in user subroutines and plugins

A full list of fixes and improvements can be found in the README.txt file that accompanies the download package.

Plugins
The US3D-1.1 plugin API has stabilized and some plugins are now becoming available for use, with several more under active development.  Plugins that are now available include the Catalytic Wall boundary condition, the Ablating Wall boundary condition, and Pressure-Dependent (Troe and Lindemann form) Reactions.  While we are finalizing the structure for direct downloads of the plugins, please email us if you would like to obtain one of the plugins listed above.  More details about plugins such as automatic mesh refinement (AMR), conjugate heat transfer, and others will be provided when these plugins are closer to being ready for testing.

VirtusAero is compiling a plugin registry to hold information about availability, compatibility, and capabilities of the various US3D plugins that are being developed.  Please send us an email if you have a plugin that you would like to have included in the listing.

Greater System Compatibility
We have increased the number of combinations of supported compilers and MPI versions and are now making US3D-1.1.6 packages available for GCC versions 5.2 – 8.2, Intel 14 – 19, and OpenMPI 1.6 – 3.1, as well as Intel MPI.  Previously, we were offering packages built on different GLIBC versions such as 2.12 (CentOS6), 2.17 (CentOS-7) and 2.27 (Ubuntu 18.04).  However, we have found that this is not necessary because Linux GLIBC has excellent backwards compatibility.  Binaries are now built based on GLIBC-2.12 (CentOS-6) and have been tested to work properly on systems running GLIBC-2.12 or later, including CentOS-7 and Ubuntu.  Along with this change we are now delivering US3D using only shared library (.so) files instead of static library (.a) files.  This change again helps to improve compatibility and robustness with respect to changes in the core US3D shared libraries and plugins.

Installation
Installation of US3D-1.1.6 is now easier with additional fixes and improvements to the installation script so that manually patching or replacing the install script should no longer be necessary.  Additional tests and feedback during installation also help to ensure that the install script gives notices about potential compatibility issues and that US3D runs properly once installed.