Report averages of quantities on (lists) of surfaces in a file versus time in transient runs |
| Users wanted to be able to record in a file in a spreadsheet format averages of various quantities versus time in transient runs.
They have as input a list of surfaces; on each of these surfaces,... |
DEFINE_ADJUST UDF for the parallel solver |
| Additional code is sometimes required to make a UDF work in parallel. One example is a DEFINE_ADJUST macro for calculating a mass weighted average or area weighted average of one or more flow... |
FLUENT - Text User Interface (TUI) commands for Tecplot export |
| How to use TUI commands in the Execute Command panel to export data from FLUENT to Tecplot. In particular, how to specify all zones and several scalars.
To produce a tecplot file named... |
FLUENT - VOF to model draining tank, swirling liquid, vortex at the drain drain. |
| It is possible to model a draining tank filled with a
swirling liquid, and to capture the vortex that forms at the drain. The goal was to pinpoint the time at which the first gas reaches the... |
FLUENT 6 - Import 2d FLUENT 4 euler-euler data file to FLUENT 6 |
| Customer would like to continue in FLUENT 6 running an unsteady Euler-Euler FLUENT 4 calculation
that took several weeks to converge. That is to say, he would like to import FLUENT 4 data into... |
FLUENT - How to define your own turbulent thermal conductivity, C_K_T |
| The UDF macro DEFINE_PROPERTY allows you to only modify laminar material properties.
When you do a turbulent simulation, FLUENT will always compute a turbulent thermal conductivity and add it to... |
FLUENT - Tips for converging a highly compressible case using the segregated solver |
| This solution contains a suggested procedure to converge highly compressible flow cases with the segregated solver.
-use incompressible (constant density) -use default limits (Solver->... |
FLUENT - A possible procedure for modeling the soaking condition in automotive underhood simulations
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| The soaking condition would be the most challenging phase of the underhood simulation. Natural convection problems in general are highly unstable, because of the non-linearity due to strong... |
How can I reuse the results from a previous Fluent run to initialize my current Fluent calculation |
| File interpolation can be used to utilize the results from a previous Fluent run to initialize the new run. This will help reduce the computation time. To do this, you will write out an... |
Face temperatures F_T(face,thread) are not available in UDF for interior faces. If required, it should be reconstructed. |
| The UDF example reconstructs the face value based on cell temperature and cell temperature gradient stored on each side of the face.
This value is copied in UDM-0 in each cell located on each side... |
How to create a moving 'fixed value' in FLUENT? |
| A fixed value can be imposed via a source term and source term can depend on time. In this way it's possible to move a 'fixed value' around the domain during the simulation.
The question becomes... |
Simulation of high temperature flame, over predicts the temperature than expected, what can be done to get a realistic temperature field? |
| Global reaction mechanisms with one or two steps inevitably neglect the intermediate species. In high-temperature flames, neglecting these dissociated species may cause the temperature to be over... |
How can I record the DPM particles for individual size groups? |
| You can record the particles for individual size groups by the following way.
Display-> particle Tracks Report Type : Step by step Report to : File Color by : Particle variables (Particle... |
I need to give temperature profile BC on a wall in ANSYS FLUENT. But the data points is such x, y, z coordinates of surface is not given but the variation with one of the axis is given. Without going for a UDF how can I get this profile on to the boundary? |
| You can try the following procedure:
1. Curve fit the data 2. Create a custom field function using the equation 3. Do not give any BCs. Patch the whole domain with this custom field... |
What gradient options is best with shell conduction zones in Fluent? |
| Least Square Cell Based is the best if you want to accurately predict temperature on shell conduction zones.
Green Gause Node Based is the next option. The problem with node-based is that it... |
I have a conjugate heat transfer problem in FLUENT 12. The energy residuals do not converge. What could be the cause and how to converge it? |
| Causes:
========= 1. Poor mesh quality: high size change, and/or high skewness, and/or coarse mesh 2. high jump in thermal conductivity 3. invalid boundary conditions 4. improper mesh... |
How can we specify both spatial and temporal temperature profile on a wall zone? |
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In some heat transfer simulations, user will want to impose a temperature profile on a given wall zone that is varying both spatially and temporally. That is, at different times, the spatial... |
How to compute the integral of a variable along a line using UDF in FLUENT?
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| Line surfaces in FLUENT have area in 2d and 2d-axi but not in 3d, so currently integrals on line surfaces are zero.
This solution provides a sample User Defined Function (UDF) that shows how to... |
How can we read the experimental/tabulated values of material properties or profiles using a UDF? |
| FLUENT provides for a variety of methods for specifying material properties, including polynomial functions, piece-wise linear functions, etc. User-defined functions can also be used to specify... |
Can you give me some basic guidance on modeling droplet evaporation in FLUENT 12? |
| Many users setup a droplet evaporation case in FLUENT and use default settings for material properties for the droplet. This is not correct as those are just placeholders. It is important to note... |
How can I compute the heat transfer coefficient in CFD-Post?
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| In CFD-Post, under File->Export, export Temperature and Heat Flux to a .csv file using the desired surface on which you want to calculate the HTC.
Set Boundary Values to Hybrid so that... |
In CFD-Post, how can we quickly create an animation of a transient problem, e.g. temperature contours on a slice moving through the time?
|
| See the PDF below:
http://www.eureka.im/downloads/faq215_KR215.pdf |
How can I get cell values of temperature in CFD-Post?
|
| See below:
http://www.eureka.im/downloads/faq203_KR203.pdf |
How to resolve warning message involving the temperature limits? |
| There are two main causes for this: shell conduction initialization and reacting flow/heat transfer issues.
If you are using Shell conduction, you must patch the shell zones using the... |
How can I suppress the warning messages about reversed flow at certain boundaries or regarding limits on certain variables such as temperature or turbulent viscosity? |
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These warning messages could indicate potential errors or inconsistencies in your problem definition within FLUENT. In other cases, they may appear only during the early convergence stages of... |