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User Interface Changes Enhance Productivity

This development note highlights some of the changes to the FLOW-3D graphical user interface that will benefit users by making model setup, simulation and post-processing easier and more robust.

Model Setup

Navigator and Workspaces

When users first open FLOW-3D version 9.3, they will notice a brand-new tab called Navigator. In the Navigator, users can create Workspaces in which multiple simulation input(prepin) files can be grouped together for ready reference.

What is a Workspace?

FLOW-3D screenshot showing how to organize simulation files into workspaces
Figure 1: New Workspaces with simulation files.

Each Workspace and each simulation file associated with that Workspace will have a directory on the hard disk. The default location for new simulation files is the directory of the Workspace in which the new simulation is located, but the user can specify other locations. The default directory where Workspace directories are saved can be specified.

Advantages of Workspaces

Workspace Examples. An engineering services company might wish to use use a distinct Workspace for each project for a client, with each simulation file in the Workspace representing various aspects of the client's design, or improvements to the model as work progresses on the job. The R&D department of a manufacturing concern has groups of simulations that are related to work on a specific development for an internal "client." Workspaces can be used to hold the simulation files for each of these tasks.

Storing files.Many users will find it useful to organize associated simulations by storing them as subdirectories in a directory together with a workspace file that essentially mirrors that directory structure. However, simulation directories from different locations on your disk can be added to and saved in a single Workspace without changing the location of the simulation file or the destination of any of the files FLOW-3D generates, such as results files, message files, and so on.

Running multiple simulations in Batch Mode.Another valuable benefit which users gain with Navigator is the ability to line up multiple projects, each with its own settings, to run in “batch mode,” such as before leaving for the weekend or on vacation. In this way, Workspaces can be used to assemble disparate simulations to be run serially, with the associated FLOW-3D files being written to the original file directory locations.

Use of Workspaces is not mandatory; users can open FLOW-3D and either start a new simulation or open an existing prepin file without organizing a Workspace, just as in prior versions.

Setting up Restart Simulations

Restart options for in the V9.3 FLOW-3D GUI
Figure 2: Restart options

Another important change to the interface is in setting up restart input files. In the new Restart options dialog box, the user can select an flsgrf file located in the directory where the prepin file is located, or browse to find a results file in any other directory. In addition, a drop-down menu shows all the time frames available for restart selection in the results file as shown in Figure 2.

Other Notable Changes:

  1. The ability to enter via dialog boxes all of the parameters required by the General Moving Object, Collision and the new Deforming Objects models, as well as for mass sources and mass-momentum sources. An example for the GMO model is shown in Figure 3.
  2. Selection of solver version (single precision, double precision, etc.), simulation units and number of processors to execute on (for users with the SMP parallel version of FLOW-3D) is now made in the Global tab of Model Setup, so that each simulation in a Workspace can have its own unique selections.
Enter parameters for each moving object in the FLOW-3D user interface
Figure 3: Moving objects setup


Several changes have been made to the process of launching and monitoring a simulation.

Changing Solver Options on the Fly

The new Runtime Options feature, which was described more fully in the Fall 2007 Newsletter, is the ability to make changes to numerical settings during a simulation to make it run more efficiently. The new Runtime Options tool allows the user to change most of the numerical options during the simulation, without the need to stop or even pause it.

New FLOW-3D simulation options
Figure 4: Simulation options

A New Approach to Launching Simulations

Simulations are now launched from the main FLOW-3D menu bar. The Finalize tab has been removed from the Model Setup tab and its function added to the Simulate tab, combining preprocessor, simulation and post processing messages in one place. There is a new selection in the main menu bar, Simulate, which gives the user options to preprocess only or to run a selected simulation, to run all simulations in a selected Workspace, or to run all open simulations.

In addition, users with multiple solver tokens will now be able to run more than one simulation from within the same instance of the FLOW-3D GUI. After launching one simulation, the user need only select another simulation in the Portfolio, then click on Run Simulation from the Simulate menu to launch the second simulation.

Simulation Graphing

Zoom in on graphical results in FLOW-3D
Figure 5: Zoom in on results

Another convenient new feature is the ability to zoom in on the graphs displayed in the Simulate window, giving the user the opportunity to more closely evaluate the progress of a simulation.

The user can zoom in on an area of interest by left-clicking and dragging his mouse across the graph. Multiple zooms are allowed. Right-clicking on the mouse backs out of the zooming.

Other Helpful Changes to the Simulate Window:

  1. When a user opens a prepin file for which a simulation has been previously concluded, the graphs and the data displayed in the Simulate window during the running of the simulation will be shown again.
  2. The graphing function scales much more dynamically as a simulation proceeds.
  3. Grid lines are displayed in the graphs.


Visualization is an area of great interest to users, and version 9.3 adds some noteworthy new post-processing features.

Faster Rendering

Because users are now simulating larger problems, their resulting flsgrf files are getting larger and larger. This is an issue Flow Science is focusing on heavily. Currently, FLOW-3D renders all iso-surfaces for all selected time frames before displaying results. To enable users to more-quickly render their 3D results, the version 9.3 post-processor writes to disk only the first selected time frame in a results file (unless the user decides otherwise). All other time frames are shown and available for selection in Display.

Displaying STL Files for Simulation Results Using GMO

Users often want to import STL files into the 3D Display window to show sharper images of their geometry. Where the GMO model was used, however, it was not possible to have the STL file track the moving object in version 9.2 or earlier versions. Now, however, results files generated with the version 9.3 solver contain data capturing the location of the STL file as it moves through the domain. This data can then be imported into the Display window by checking a new STL check box in the Analyze tab.

Two boats passing in a flow simulation show a sharper geometry display
Figure 6: Sharper, crisper STL file display.

Other Post-Processing Additions:

A mesh slice of multiple mesh blocks in FLOW-3D
Figure 7: Mesh slice function
  1. Users can use the Mesh Slice function on multiple mesh blocks in Display (see Figure 7).
  2. New icons in the Display tool bar allow the user to:
    • Directly print images.
    • Display and move the Time reading.
    • Launch animations.
  3. New still-image output options are available in 3D Display (jpeg and png) and 2D Display (jpeg).
  4. Users can display the length scale for X, Y and Z in 3D Display.


In summary, the upcoming release of FLOW-3D has a substantial collection of very useful and practical improvements for users. We plan to continue developing this exceptional user interface that is modern, intuitive and comprehensive.