Tutorial 1: Simple Stationary Flow Network Modelling


This exercise will walk the user through building a simple, three element flow circuit using basic chamber and element types based on the defined geometry. The user will learn how to:

  • Drag and drop entities onto the screen in order to create the network
  • Edit chamber properties
  • Edit element properties
  • Check the model
  • Run the model
  • Post-process the model
  • Chamber Types: Plenum
  • Element Types: Standard Tube, Conventional Orifice
  • Fluid: Air


Flow network simulates air flowing through a long pipe with a 1/2“ inner diameter into a large tank. The air then exits the tank through 2 exits.

Figure 1.01: Simple Stationary Model Chamber Layout

Step 1: Create Model Entities

  1. Drag and drop three boundary plenums and one non-boundary plenum from the Object Tree to the Graphical Workspace. See figure 1.02

Figure 1.02: Simple Stationary Model Chamber Layout

  1. Drag and drop tube element, and connect upstream chamber to boundary chamber 1, and downstream chamber to non-boundary chamber 4.
  2. Drag and drop two orifice elements, each one connecting upstream to non-boundary chamber 4 and to each of the remaining boundary chambers. See Figure 1.03.
  3. Save new model database by selecting File → Save As, and specifying a filename.

Figure 1.03: Simple Stationary Model, Chambers and Elements

Step 2: Modify Entity Properties

  1. Select boundary chamber 1 (inlet), and set static pressure to 100 psi and relative total temperature to 400 F.
  2. Select both (shift + click) boundary chambers 2 and 3 (exits).Set static pressure to 80 psi and relative total temperature to 100 F.
  3. Select tube element. Set diameter to 0.5in, length to 25ft, and turn Heat Transfer to adiabatic (under Advanced Options → Heat Addition).
  4. Select both (shift + click) orifice elements. Set diameter to 0.5in (may have to switch Area/Diameter drop down to Diameter first), and Cd to 0.65.
  5. Save database by selecting the save icon in the upper left corner of the toolbar

Step 3: Check Model and Run

  1. Select checkmark icon from the top toolbar to check the model for warnings/errors.
    • An error should populate stating that the internal chamber has not been initialized
  2. Select the initialization icon from the toolbar, and pick Start. Accept values once flow solver has converged.
  3. Select run icon from toolbar. Run Flow Simulator.

Step 4: Post-process

  1. Results file (*.res) should automatically be loaded into GUI. If not, it can be selected via File → Load Result File
  2. By default, both chamber and elemental results are displayed in the graphical workspace. See Figure 1.04.
  3. Customization of the displayed results is accessible within Settings → Display Options

Figure 1.04: Simple Stationary Model w/ Results Displayed

Model Folder Contains

simple_stationary.JPG Image file
simple_stationary.flo Flow Simulator ASCII-based database file.
simple_stationary.res ASCII-based Flow Simulator results file. This can be loaded into Flow Simulator to view chamber and elemental solution data
convhist_fi.out ASCII-based convergence output from Flow Simulator solution.