What is in:Flux?

in:Flux is CFD software that analyses ventilations and gas dispersions within complex geometries. It is aimed at all engineers, including those who have never previously performed a CFD themselves. The speed and simplicity of in:Flux is unrivalled, so that organizations such as yours can now carry out CFD modeling at a fraction of the time and cost associated with other CFD products.

Why is in:Flux Useful?

Many of the tasks that require a high level of CFD expertise are handled automatically by in:Flux. For example, meshing is entirely automatic – the mesh will refine around geometry and regions of high gradients. Numerical discretization schemes and physical models are all automatically set, as are boundary conditions and convergence criteria. The user is simply required to input the required wind speeds and directions, and point sources of gas emissions and wait for the solution to complete. This level of automation provides assurance of high quality CFD results.
Once the simulation has finished, the user can add streamlines, contour plots and 3D isosurfaces to analyze the data. All the post-processing can be output to images files for reporting.

What Makes in:Flux Different?


The in:Flux documentation is always being updated. We strive to develop these tutorials and guides to go over all the major features of the software. Throughout 2020 and beyond Insight Numerics will be pushing updates as our validation cases are finalized.
As some of the more advanced features have not yet been covered in the guide, please feel free to email us inquiries as we continue to release updates.
As we continue to improve in:Flux and making it more accurate to match experimental data, the tutorials may lag behind the most current in:Flux build. Thus, when you are going through the tutorials you may receive slightly different results on your version than results shown and displayed in this help file. If you have any questions about the results you are receiving, feel free to contact us at info@insightnumerics.com and we will be happy to help you.
Building blocks of an in:Flux project
The steps below list the procedure of carrying out a dispersion simulation using in:Flux. The steps should be carried out chronologically as each step is based on the previous, the exception being post-processing which can be viewed after ventilation simulations have complete.
Steady-State Simulations
in:Flux simulations are automatically set to be steady-state. This means that there is no concept of time – all in:Flux is trying to simulate is the established gas plume.
In reality of course, there will always be a finite inventory, so upstream pressures will drop, flow rates will decrease, until eventually nothing comes out of a gas leak. If this happens very quickly, then steady-state simulations such as these are not appropriate – you have to use a transient CFD simulation. However, it is quite rare that you really need to go to a full transient, because “quickly” usually means “quick relative to the plume establishing a steady state”. If you look at actual gas leaks, the plume establishes very fast in the near-field (e.g. lengths associated with offshore leaks). Clearly if you are interested in the very far-field, then the plume establishment takes longer.
So you only need full transient simulations when the decay of the release rate is fast relative to the time it takes for the plume establishment. As mentioned, this is not normally the case.
Transient Simulations
As of version 1.1, in:Flux allows users to run transient simulations - giving the ability to view flow characteristics at a specified time. When adding a dispersion to the project, simply  change the 'Scheme' under the Transient section. Additionally, a shutdown (ESD) time and inventory volume may be added to high pressure gas leaks via the add items tab.
Future Developments
Keep watch for updates regarding the release of new features to in:Flux including combustion models and multi-phase leaks.