ACU-T: 2000 Turbulent Flow in a Mixing Elbow


Prior to starting this tutorial, you should have already run through the introductory tutorial, ACU-T: 1000 HyperWorks UI Introduction. To run this simulation, you will need access to a licensed version of HyperMesh and AcuSolve.

Before you begin, copy the file(s) used in this tutorial to your working directory.

Since the HyperMesh database (.hm file) contains meshed geometry, this tutorial does not include steps related to geometry import and mesh generation.

Problem Description

The problem to be addressed in this tutorial is shown schematically in Figure 1. This is a typical industrial example for mixing in a pipe by injecting high-velocity fluid from a small inlet into relatively low-velocity fluid in the main pipe. It consists of a 90° mixing elbow with water entering through two inlets with different velocities. The geometry is symmetric about the XY midplane of the pipe, as shown in the figure

Figure 1. Schematic of Mixing Elbow

Open the HyperMesh Model Database

  1. Start HyperMesh and load the AcuSolve user profile.
    Refer to the HM introductory tutorial, ACU-T: 1000 HyperWorks UI Introduction, to learn how to select AcuSolve from User Profiles.
  2. Click the Open Model icon located on the standard toolbar.
    The Open Model dialog opens.
  3. Browse to the directory where you saved the model file. Select the HyperMesh file and click Open.
  4. Click File > Save As.
    The Save Model As dialog opens.
  5. Create a new directory named MixingElbow_Turbulent and navigate into this directory.
    This will be the working directory and all the files related to the simulation will be stored in this location.
  6. Enter MixingElbow as the file name for the database, or choose any name of your preference.
  7. Click Save to create the database.

Set the General Simulation Parameters

  1. Go to the Solver Browser, expand 01.Global, then click PROBLEM_DESCRIPTION.
  2. In the Entity Editor, set the Turbulence Model to Spalart Allmaras.

    Figure 2.

Set Up Boundary Conditions

By default, all components are assigned to the wall boundary condition. In this step, you will change them to the appropriate boundary conditions and assign material properties to the fluid volumes.
  1. In the Solver Browser, expand 12.Surfaces > WALL.
  2. Click Large_Inlet. In the Entity Editor,
    1. Change the Type to INFLOW.
    2. Set the Inflow type to Average velocity.
    3. Set the Average velocity to 0.4 m/s.

    Figure 3.
  3. Click Small_Inlet. In the Entity Editor,
    1. Change the type to INFLOW.
    2. Set the Inflow type to Average velocity.
    3. Set the Average velocity to 1.2 m/s.
  4. Click Outlet. In the Entity Editor, change the Type to OUTFLOW.

    Figure 4.
  5. Click Symmetry. In the Entity Editor, change the Type to SYMMETRY.

    Figure 5.
  6. Click Wall. In the Entity Editor, verify that the Type is set to WALL.

    Figure 6.
  7. Click Fluid. In the Entity Editor,
    1. Change the Type to FLUID.
    2. Select Water_HM as the Material.

    Figure 7.
  8. Save the model.

Compute the Solution

In this step, you will launch AcuSolve directly from HyperMesh and compute the solution.

Run AcuSolve

  1. Turn on the visibility of all mesh components.
    For the analysis to run, the mesh for all active components must be visible.
  2. Click on the ACU toolbar.
    The Solver job Launcher dialog opens.
  3. Optional: For a faster solution time, set the number of processors to a higher number (4 or 8) based on availability.
  4. The Output time steps can be set to All or Final. Since this is a steady state analysis, the Final time step output is sufficient.
  5. Leave the remaining options as default and click Launch to start the solution process.

Post-Process the Results with HyperView

Once the solution has converged, close the AcuProbe and AcuTail windows. Go to the HyperMesh window and close the AcuSolve Control tab.

Open HyperView and Load the Model and Results

  1. In the HyperMesh main menu area, click Applications > HyperView.
    Once the HyperView window is loaded, the Load model and results panel should be open by default. If you do not see the panel, click File > Open > Model.
  2. In the Load model and results panel, click next to Load model.
  3. In the Load Model File dialog, navigate to your working directory and select the AcuSolve .Log file for the solution run that you want to post-process. In this example, the file to be selected is MixingElbow.1.Log.
  4. Click Open.
  5. Click Apply in the panel area to load the model and results.
    The model is colored by geometry after loading.

Create Contour Plots of Pressure and Velocity

In this step, you will create pressure and velocity contour plots on the symmetry plane.
  1. In the Results Browser, expand the list of Components.
  2. Click the Isolate Shown icon then click the Symmetry component to turn off the display of all components in the graphics window except the Symmetry component.

    Figure 8.
  3. Orient the display to the xy-plane by clicking on the Standard Views toolbar.
  4. Click on the Results toolbar to open the Contour panel.
  5. Under result type, verify that Velocity(v) and Mag are selected.
  6. Click the Components entity selector. In the Extended Entity Selection dialog, select Displayed.
  7. Click Apply.
  8. In the panel area, under the Display tab, turn off the Discrete color option.

    Figure 9.
  9. Click the Legend tab then click Edit Legend. In the dialog, change the Numeric format to Fixed then click OK.

    Figure 10.
  10. Change the result type to Pressure(s) then click Apply to view the pressure contour on the symmetry plane.

    Figure 11.


In this tutorial, you worked through a basic workflow to set up a CFD model, carry out a CFD simulation, and post-process the results using HyperWorks products, namely AcuSolve, HyperMesh, and HyperView. You started by importing the model in HyperMesh. Then, you defined the simulation parameters and launched AcuSolve directly from within HyperMesh. Upon completion of the solution by AcuSolve, you used HyperView to post-process the results and create contour plots.