New Integrated Post-Processor

The new online post-processor integrated into SimScale is compatible with all your old/new projects and simulations that you create.

This document provides a detailed overview of SimScale’s new post-processor. It can be used as a general source of information and also as a follow along. For easy understanding, an example of a fluid flow through a pipe is used to relate the features to an actual simulation.

A post-processing tutorial for the same already exists and interested readers are advised to follow it for a finer learning experience.

Post-Processing

Firstly, when a simulation is successful or has results available, the run dialog box will prompt a ‘Post-process results’ button. Clicking this button or selecting ‘Solution Fields’ in the simulation tree will open the results in the online post-processor.

Overview

The post-processing environment contains a number of functions and filters that allow you to obtain a visual representation of the results. The figure below contains an outline of the post-processor:

1. Visualization and selection modes toolbox: Here you are able to change (from left to right) the visualization and render mode of the geometry, as well as choose the selection mode between Select volume and Select face.
2. Frame selection toolbox: This part of the post-processor is especially useful in transient simulations. It allows you to navigate through the various result sets that were saved during the simulation run.
3. Additional tools: In the top-right corner of the post-processor, you will find useful options, such as the Screenshot, the Bulk calculator, and the Inspect point feature. An on/off toggle for the legend is also available.
4. Viewer: This is where you can see results. A series of quick selection tools are accessible by right-clicking on the viewer.
5. Orientation cube: An orientation cube, based on the directions of the global coordinate system, will help you to orient the model in a specific direction.
6. Filters: A number of filters, such as Cutting plane and Particle trace, are available in the post-processing environment. They are useful to obtain more insights into your results.

Legend

To use the legend feature:

1. Make sure that the Parts Color toggle is enabled.
2. Next to Coloring, select any parameter to plot on the faces of the model. From the drop-down menu, navigate to Velocity Magnitude, for example.
3. Please ensure that the Toggle legend icon is enabled. At this point, the scale will be visible at the bottom of the viewer.

The scale bar is highly customizable, including the displayed range, units, and number of divisions. Figure X shows the details:

1. By clicking on the minimum value of the scale range, you can set your own custom number.
2. Likewise, the maximum value of the range can also be changed.
3. In the drop-down menu, next to the parameter’s name, you can change the units displayed on the scale.
4. By right-clicking on the scale, we can change the color schemes, number of scale divisions, or even use a continuous scale.

The number of scale divisions is 10 by default. To raise the number of scale divisions, right-click on the scale and adjust the Division number accordingly.

Bulk Calculator and Inspect Point

The Inspect point feature is useful to obtain an accurate read on a specific point of the surface. For example, to inspect the velocity magnitude on the top inlet:

1. Enable the Inspect point toggle on the top right of the viewer.
2. Click on any point within the top inlet face. In this case, the inlet is defined by a boundary condition, so the velocity is fixed at 1 \(m/s\).

Another very useful option is Bulk calculator. When this option is on, you can obtain detailed information about faces, volumes, and cross-sections (created with cutting planes).

For example, using the bulk calculator, we can easily obtain an average for the velocity magnitude on the outlet. Figure X shows the steps:

1. Ensure that the Bulk calculator is toggled on
2. Enable the Select face option. Note that, if your Inspect point toggle is still on, you will need to disable it to select a face. If that’s the case, simply click on the Inspect point toggle to disable it
3. Click on the outlet face to select it. An information box will appear in the bottom left corner of the viewer, containing minimum and maximum values, averages, integrals, and additional information related to the selected parameter (velocity magnitude).

Note that the information displayed by the bulk calculator is dynamic. You can select various faces and also change the parameter that is being analyzed. To make the information box disappear, you can toggle off the Bulk calculator.

Visualization and Selection Modes

The selection modes are designed to quickly select and modify the visualization of the geometry. By right-clicking on the viewer, you will have access to a number of quick selection options. Some visualization options, such as Hide selection, are also available to hide the selected parts.

The Hide selection feature is especially useful whenever we have an enclosure around the regions of interest (in external aerodynamic simulations, for instance). To make the parts visible again, right-click on the viewer, and select ‘Show all’:

Cutting Plane

With a Cutting plane filter, you are able to slice the domain and visualize parameters of interest on the plane. Additional options, such as plotting velocity vectors, are also available.

To create a cutting plane, click on ‘Add Filter’ and select ‘Cutting Plane’ from the drop-down menu:

Cutting planes are highly customizable. For instance, you can define an Orientation, Opacity, plot Vectors, among other options.

Now the magnitude of the velocity is plotted on the plane. To add Vectors to the plane:

Iso Volume and Iso Surface

The Iso surface filter is useful to show cells that match a given variable value. For example, to see where the velocity magnitude is exactly 1 \(m/s\) an Iso surface filter, with the following configuration can be created:

Within Iso scalar and Iso value, the user decides the criteria for highlighting the cells. With Coloring, you can choose a parameter color the cells that satisfy the criteria.

The Iso volume filter works the same way. However, instead of defining a single Iso value, the user defines an Iso value range to highlight the cells.

Hence, to highlight the regions with gauge pressure levels between -2000 and 100 \(Pa\) one should proceed as follows:

1. Click on the ‘Add filter’ button and select ‘Iso volume’
2. Define ‘Pressure’ as an Iso scalar.
3. Expand the ‘Iso value range’ tab, so it shows the minimum and maximum Iso values. Please set those to ‘-2000’ and ‘100’, respectively
4. Toggle Parts color on, so we can have a clearer view of where the highlighted regions are
5. Change the render mode to ‘Translucent surfaces with wireframe’

Particle Trace

A Particle trace filter generates streamlines from a seed face. They can be useful to observe recirculation spots and flow patterns, allowing us to improve the designs.

Configuring a particle trace is very simple. After creating the filter, the user needs to select a seed face, from where the streamlines are generated. Oftentimes, the inlets and outlets are good candidates for seed face. With Pick Position enabled, you will be able to select one of the inlets as a seed face, as in Figure 14:

Animation

The animation filter is often used on two occasions:

• In combination with a particle trace filter
• To animate the results of a transient analysis

Please ensure that the Animation type is set to Particle trace. Afterward, we can simply click on the ‘Play’ button, to generate an animation of the streamlines. Note that you can change the number of Steps, to control the number of frames of the animation.

Custom Camera Position

Simulating a project and drafting a professional report might require recreating the same angles and screenshots for all the visual results. To take advantage of this consistency in your animations and images use the custom camera postion. This feature can be seen at the top left of the orientation cube.

To learn more about this handy feature refer to our knowledge base article.

Troubleshooting

In case of problems with the post-processor, please reset it to the default settings. To do that, simply right-click on Solution Fields and select ‘Reset to default’. This will re-start the post-processor in a stable configuration.

Legacy Interface

As default, the Solution Fields loads in the New Beta Interface. However, you can still access the Legacy Interface. To switch between the New Beta Interface and the Legacy Interface, simply right-click on Solution Fields and select ‘Open in legacy interface’.

Last updated: May 20th, 2021