August 2025 critical fixes

August 2025 fixes were published on 14 August 2025.

Bug 62443: For models using time-dependent tables for free molecular heating, periodic interpolation is not applied outside the defined range of the table

Fixed versions: 2506.2, 2412.10

Prior to the fix, when using free molecular heating boundary conditions with time-dependent flux tables, periodic interpolation was not applied by the thermal solver when it was enabled. As a result, flux values remained constant beyond the defined time range of the table. This issue has now been resolved.

Bug 62464: Improve the distribution of emitted rays on skewed quadrilateral elements for GPU radiation calculation methods

Fixed versions: 2506.2, 2412.11

In GPU radiation calculations, quadrilateral elements are divided into two triangles. When a quadrilateral element is skewed, the resulting triangles may exhibit significantly different areas. Assigning an equal number of rays to each triangle can lead to biased results favoring the smaller triangle. To address this, the distribution of rays is now weighted according to the area of each triangle.

Bug 97825: A co-simulation analysis involving orbital fluxes produces incorrect results due to improperly initialized flux values in the thermal solver

Fixed versions: 2506.2, 2412.10

A defect in the thermal solver affecting models with co-simulation and radiative heating has been resolved. Previously, radiative fluxes were incorrectly initialized to -10 instead of 0, leading to an inaccurate simulation. This issue has now been addressed to ensure correct initialization and consistent, reliable results.

Bug 106913: Incorrect coupling area values are computed in post-processing for selections assigned multiple boundary conditions

Fixed versions: 2506.3, 2412.11

In models where multiple boundary conditions are applied to the same selection, the coupling area reported by post-processing was incorrect. The coupling area for only one of the boundary conditions applied to the element would be displayed. This issue has been resolved. The coupling area now accurately represents the combined coupling area for all boundary conditions applied to the element and aligns with the values reported in the *.bcdata summary file. Other results, such as temperature and convection coefficient, remain unaffected by this change.

User Story 107757: Retrieve initial conditions from the external solver rather than using hard-coded zero values for a co-simulation analysis

Fixed versions: 2506.2

For co-simulation models, initial conditions from the external solver were previously set to zero. The initial values are now correctly retrieved and updated in the thermal solver for both FMI 2.0 and FMI 3.0 standards.

User Story 110467: Implement an element-based method to model radiative heat transfer between elements for the finite element method to accelerate initialization and matrix assembly when using parabolic elements and/or black body thermo-optical properties

Fixed versions: 2506.3, 2412.11

A new element-based method has been implemented in the thermal solver for the finite element method to compute the radiative heat transfer between elements. This technique aims to improve performance during initialization and matrix assembly, especially in cases with parabolic elements or where radiative heat transfer does not include Oppenheim elements.

Bug 112219: The 'Total Time ON' values reported in the *.ThermostatsReport.csv file are inaccurate when automatic time stepping is used

Fixed versions: 2506.3, 2412.11

Previously, thermostats and active heater controllers were incompatible with automatic time stepping. The thermal solver was updated to support this functionality.