Workflow and Output

After ultraFluidX has been launched, it will read in the tessellated surface mesh, as well as the simulation parameters, and then start to generate the volume mesh based on the specified refinement zones.

When the volume mesh is ready and the surface mesh has been optimized according to the respective parameters, such as <triangle_splitting>, ultraFluidX will start the actual simulation on the GPUs and perform as many iterations on the coarsest refinement level as specified via <num_coarsest_iterations>. On higher refinement levels, the necessary number of sub-iterations will be performed according to the mesh size of the respective level.

Terminal Output

During the simulation, ultraFluidX will continuously write some output to the terminal, for example, the current coarsest iteration and the corresponding physical simulation time, the current drag, lift and side force coefficients, as well as the averaged computational performance and the presumable end of the simulation.

File Output

Additionally, ultraFluidX will create the following files and folders in the output path, if specified, or in the current run directory (if option -o was omitted, see below) for the output of various result types:

uFX_coefficientsData

Folder including the instantaneous and averaged aerodynamic coefficients (uFX_coefficients_Inst.txt and uFX_coefficients_Avg.txt) and additional coefficient data per section or part, according to input in the <output> - <aero_coefficients> section.

This folder contains information on the instantaneous and averaged mass flow rates in the porous medium, if any, according to the <sources> - <porous> section.

uFX_fullData

Folder including the full output dataset according to the specifications in the <output> - <general> section. This folder contains all the output in EnSight Gold format.

Note: ultraFluidX outputs the data in a distributed manner, per MPI rank. Additionally, a so-called “Server of Servers” file (uFX_output.sos) will be created that refers to the *.case files, per rank:uFX_output_#variable _RANK#rank_#timestep.data. Files that contain the actual result data, per variable, per rank, and per time step.

uFX_output_RANK#rank.geo: Files that contain the volumetric mesh data, per rank.
uFX_output_RANK#rank.case: Individual case files that collect the available data, per rank.
uFX_output.sos: “Server of Server” file that collects all the distributed information and links the individual *.case files. The *.sos file can be used by many visualization tools to handle the *.case files, as if they were one output file.

ultraFluidX also offers specific output files for processing the result data with AcuFieldView:

uFX_output_RANK#.bcf: “Binary case file” that collects the available data, per rank.
uFX_output.layout: Layout file that collects the distributed *.bcf files.

Note: ultraFluidX can also merge the individual files, per rank after the simulation is completed. Refer to the <output> - <general> - <merge_output_files> option.

ultraFluidX offers to merge files manually by specifying the -merge option.

uFX_meshData

Folder with all mesh related output, including the mesh preview (if activated, see <meshing> - <general> - <mesh_preview>), the restart file (if activated, see <meshing> - <general> - <mesh_export>) and a list of void triangles that were removed from the specified tessellated surface mesh during meshing, if any.

uFX_surfaceData

Folder containing the surface data of the simulation results (output with respect to the respective parameter <output_frequency>), including the output of partial surface, if activated in the <output> - <partial_surface> section.

The output has the same structure as the content of the uFX_fullData folder.

uFX_volumeData

Folder that contains the partial volume output, if specified in the <output> - <partial_volume> section.

The output has the same structure as the content of the uFX_fullData folder.