Getting Started

Overview

In this section, we will build, run, and post-process a simple model of an agitated tank. In doing so, we will use all three components of the M-Star CFD Package.

The Graphical Interface

Let’s quickly discuss the M-Star Build graphical interface. This program is also sometimes referred to as the “GUI” for brevity.

_images/gui-layout-v2.png

Model Tree

This lists out all components of the simulation, including moving geometry, static geometry, fluid models, scalar fields, particles, etc.

Components

Each component represents a part of the simulation input. You click on each Component to display all the Properties associated with it. You may also right click on the component to bring up any supported actions, such as moving or rotating geometry.

Property Grid

This window lists all the inputs for the selected component. Generally, the most common inputs are shown at the top of the list, and less used or advanced options are at the bottom.

3D View

This window shows your model geometry and other defined components. You can change the style and toggle annotations on and off through the View menu.

  • Rotate view - Hold RIGHT mouse button and move

  • Pan view - Hold MIDDLE mouse button and move

  • Zoom - Mouse Wheel or view zoom tools

Command Window

This window displays any messages to the user. Errors during model set-up will appear here. You can remove the command window by pressing X in the dock panel. Bring it back by going to View-Toggle Command Window

The First Model

This model will be created and running in a matter of minutes. We will use parametric Brep generation to create an agitated system with a tank and Rushton impeller. Before you get started, you’ll want to be sure the software is installed properly and licenses are set-up. Now, if you haven’t already, open M-Star Build from the Windows Start Menu.

Units

Look at the center bottom of the program window to take note of the system. You can change this under the Edit->Unit Settings menu. The default length unit is meters.

Users should always check the active unit system when building a model

Create a tank

  1. Create this geometry by clicking Create - Static Body.

  2. You are now presented with the Add Geometry form

  3. Select Tank Cylindrical in the list and click OK

  4. Two objects were created: Static Body and its geometry “Tank Cylindrical”.

  5. Click on the Tank Cylindrical to bring up its input properties. Try changing a few parameters such as End1 and Diameter to see the parametric geometry update

Create an impeller

  1. Create an impeller by clicking Create - Moving Body

  2. You are now presented with the Add Geometry form

  3. Select the Rushton and click OK

  4. Two objects were created: Moving Body and its geometry “Rushton”.

  5. Click on the Moving Body to bring up its parameters

  6. Change the impeller speed by adjusting the Rotation Speed input.

  7. Notice here on the Rotation Speed input there is a button “…” you can press. This brings up the Expression Editor. Certain inputs have this ability. In general the expression syntax represents that of the C programming language. On application of this in the context of Rotation Speed is that you may want to implement a customized start up ramp speed, or implement an On/Off pulse.

Moving the Impeller

  1. Click on the Moving Body component in the model Tree

  2. Click the Translate button to start a translate action

  3. The translate form appears

  4. In Free translate mode, you may now interactively move the geometry within the 3D view by dragging the trihedron axis. So for example you can click on the X axis that appeared in the 3D view near the Moving Body and move it along the X axis.

  5. Try moving the impeller somewhere in the tank to get familiar with how this works

  6. Click OK to apply the translation to the model component

Save the Model

# Click File - Save as to save this model

Run the simulation

  1. Click Run in the main toolbar

  2. Select a case directory. You should create a new case directory for each simulation that you run.

  3. The M-Star Solver GUI is displayed

  4. Select the number of GPUs or CPUs you want to use. By default, this number should be equal to the number of physical GPUs or CPUs in the system.

  5. Click Run to execute the simulation

In a moment, you should see output appearing in the working directory. Wait a few minutes while the simulation runs. When you see the simulation time has advanced past 1.0s, close the simulation command window to end the process.

Post-Process

Open M-Star Post by going to the Windows Start Menu and clicking M-Star->M-Star Post . Open the output directory “out” that was created in your case directory. M-Star Post loads in all available data and begins plotting certain statistics files.