POLYFLOW - zero pivot for the PRESSURE (triangles and tetrahedra along boundaries) |
The calculation terminates with the error message "zero pivot for the pressure". It usually happens on a mesh involving triangles and tetrahedra along... |
Implementation of Mixing Length Model in FLUENT ( also called zero equation model or Algebraic Model) |
I can find that FLUENT-6.1.22 has a mixing length turbulence model which can be activated through the TUI command;<br><br>/define/models/viscous/mixing-length?... |
How to export acoustics data from Fluent to Sysnoise? |
How to export acoustics data from Fluent to Sysnoise?<br>Sysnoise needs 3 types of files from Fluent:<br>.index<br>.asd<br>.data<br><br>Only one .index and one... |
FLUENT6: transient simulation: stop iterating (and advance to next time step) based on custom convergence monitor |
Residuals as the sole automatically evaluated convergence criteria don't always satisfy our needs:<br>In an unsteady simulation, we want to stop iterating for the current time step... |
Icepak: Patching temperatures for transient runs |
In order to patch temperatures for transient runs use the following method.<br>I'm giving an example for temperature, since that's usually the... |
Running FiDAP/FISOLV/FIPOST in batch mode (one single run) |
Need to execute a fidap job via FIPREP/create(fisolve)/run(...) then follow this with a batch post-processing job in FIPOST all within the same fidap run.<br><br>This way, after the... |
Determining the amount of time fluid spends in high shear regions |
For certain applications (e.g., liquid-liquid multiphase reactors, bioreactors), the amount of time the fluid spends in the high strain regions near impellers and baffles is a key parameter. The... |
How to monitor the number of particles in the domain |
For steady flow simulations in which unsteady particle tracking is used, the total number of dpm parcels in the domain should be relatively constant when the solution is converged. Fluent does... |
Cortex received a fatal signal (ILLEGAL INSTRUCTION) |
Comments: When starting FLUENT or TGRID on an AIX 5.2 system, the Cortex process fails to start and gives the message:<br><br>Error: Cortex received a fatal signal (ILLEGAL... |
POLYFLOW - Error message "Error in list1d, Invalid qconnec initial seed" |
A POLYFLOW calculation is aborted with the error message "Error in list1d, Invalid qconnec initial seed" generated beyond the information on the evolution strategy. The trouble... |
POLYFLOW - identifying the best mesh domain decomposition and optimisation (memory) |
How can a user identify the best mesh decomposition for running a simulation when limited memory is available, without running a long sequence of jobs?<br>On Unix machines, there is a tool... |
POLYFLOW - How to write out output result files for last time step only ? |
For evolution and time-dependent simulations, POLYFLOW usually writes all requested output files at each step, unless otherwise specified. For large 3D cases, especially, this can require a... |
Fluent 6.2.7: UDF modifications for Hexcore and non-conformal adaption, Parent cells |
A UDF that runs perfectly fine on tet, hex and hybrid meshes gives a segmentation error with hexcore. The UDF goes down to the cell face level c_face_loop<br><br>The original UDF looks... |
clear domain corrupts the grid |
When clear a domain in tgrid, it might corrupt the whole mesh. This happens if you create your volume mesh, which contains more than one volume, in Gambit and later on realized that you want to... |
Fluent: How to take a 2d simulation result to initialize a 3d simulation |
Imagine you have a 2d cas and dat file (for example 2d channel) and would like to use these 2d results to initialize the 3d simulation (3d channel). The 3rd direction is straight, ie. it is not... |
UDFs to implement pressure-drop vs massflow rate data (in a given direction) for a fluid zone |
This solution describes a UDF that can be used for easy setup of 1D resistance<br>inside a fluid zone given the pressure-drop vs mdot data (for a direction) in<br>tabular... |
Mirroring an ip file |
This solution describes a FORTRAN program which will flip a given interpolation file.<br><br>It could be used for the following situation:<br> - user has solved a case on half... |
POLYFLOW - What is the maximum available swap? (Memory) |
Large simulations may require significant computational resources. How to identify the available resources?<br>A distinction should be made between the available swap space on a machine and... |
Accesing the corresponding cells on either side of a wall - wall shadow zone. |
It is sometimes necessary to reference the cells on either side of the wall/wall-shadow zone. Mostly to get the temperature difference. But F_C1 does not work here. Instead, there are a couple of... |
POLYFLOW - obtaining the first solution at an assigned value of S (evolution) or t? |
In evolution or transient calculations, how can one obtain the first solution at a given value of S (evolution parameter) or time?<br>Let us assume that the initial step at S_ini succeeds,... |
y plus macro in a udf |
In a udf, you might want to access y+ value. For instance, you may want to export y+ when exporting heat transfer coefficient.<br>F_STORAGE_R(f,thread,SV_WALL_YPLUS) gives you y*... |
setting the hydraulic diameter when inlet is split by a symmetry plane |
A common question is whether it is necessary to change the value for the hydraulic diameter when splitting a flow boundary condition by a symmetry plane. For example, for a square with the side... |
POLYMAN -how to effectively change the setting "BLOCS 20" for the POLYFLOW solver? |
choosing "BLOCS 20" in POLYMAN does not seem to have any effect on the POLYFLOW solver.<br>In POLYFLOW V3.10.0, the default is 'BLOCS 60' for Windows and Linux... |
POLYFLOW - result files are not found for a data file created on PC and run on a UNIX machine |
when you run on UNIX a dat file that has been generated with POLYMAN on Windows, it may happen that output files (results) are not found. This originates from the fact that characters are used... |
DPM tracking coupled with standard k-omega turbulence model in v6.1.22 parallel solver |
You may have an error like<br><br>0 (....srcmpsystem.c@1210): mpt_read: failed: errno = 10054<br><br>for DPM particle tracking in Fluent 6.1.22 parallel solver, when the... |