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Tutorials
Tutorials show you how to use Simcenter STAR-CCM+ for various applications in a step-by-step format with recommendations for setup, initialization and steps of the solution process specific to the application. Macro and simulation files are available for download for a large proportion of cases.
Aeroacoustics
The tutorials in this set illustrate various Simcenter STAR-CCM+ features for solving aeroacoustic simulations.
DES and FW-H On-The-Fly: Noise from a Cylinder (Unsteady Analysis)
In the previous section of this tutorial, you completed the steady-state analysis runs for qualifying the volume mesh. In this section, continuing from the previous simulation file, you set up the final transient run for an unsteady analysis of the near field and an FW-H analysis of the far field.
Results Analysis
Compare the peaks in the spectra with the Mesh Frequency Cutoff plot from the final steady-state simulation.

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Tutorials
Tutorials show you how to use Simcenter STAR-CCM+ for various applications in a step-by-step format with recommendations for setup, initialization and steps of the solution process specific to the application. Macro and simulation files are available for download for a large proportion of cases.
- Using Tutorial Macros and Files
  Macros, input files, and final simulation files for a range of tutorials are provided as an optional download package on the Support Center website. These macros and final simulation files are provided as an aid to the written tutorials, so that you can check your final results against the downloaded files, or against a simulation that is built and run using the macros.
- Introduction
  Welcome to the Simcenter STAR-CCM+ introductory tutorial. In this tutorial, you explore the important concepts and workflow. Complete this tutorial before attempting any others.
- Foundation Tutorials
  The foundation tutorials showcase the major features of Simcenter STAR-CCM+ in a series of short tutorials.
- Geometry
  The tutorials in this set illustrate various Simcenter STAR-CCM+ features for creating and working with parts and 3D-CAD.
- Mesh
  The tutorials in this set illustrate various STAR-CCM+ features for building CFD meshes.
- Incompressible Flow
  The tutorials in this set illustrate various Simcenter STAR-CCM+ features for incompressible fluid flows as well as porosity and solution recording
- Compressible Flow
  The tutorials in this set illustrate various Simcenter STAR-CCM+ features for compressible fluid flows as well as harmonic balance.
- Heat Transfer and Radiation
  The tutorials in this set illustrate various Simcenter STAR-CCM+ features for heat transfer, radiation, and thermal comfort.
- Multiphase Flow
  The tutorials in this set illustrate various Simcenter STAR-CCM+ features for simulating multiphase fluid flow problems
- Discrete Element Method
  The tutorials in this set illustrate various Simcenter STAR-CCM+ features for simulating Discrete Element Method problems
- Motion
  The tutorials in this set illustrate various STAR-CCM+ features for simulating problems with moving geometries and meshes, dynamic fluid body interaction, and rigid body motion:
- Reacting Flow
  The tutorials in this set illustrate various Simcenter STAR-CCM+ features for simulating reacting flows such as combustion.
- Solid Stress
  The tutorials in this set illustrate various Simcenter STAR-CCM+ features for computing deformation, strain, and stresses in solid regions. They also show how such computations can be coupled to the fluid behavior in an analysis of fluid-structure interaction.
- Aeroacoustics
  The tutorials in this set illustrate various Simcenter STAR-CCM+ features for solving aeroacoustic simulations.
  - Broadband Models: Noise from a Cylinder (Preparation)
    This tutorial demonstrates how to set up aeroacoustics problems in Simcenter STAR-CCM+. The flow around a cylinder is used in the simulation to describe the required steps.
  - DES and FW-H On-The-Fly: Noise from a Cylinder (Unsteady Analysis)
    In the previous section of this tutorial, you completed the steady-state analysis runs for qualifying the volume mesh. In this section, continuing from the previous simulation file, you set up the final transient run for an unsteady analysis of the near field and an FW-H analysis of the far field.
    - Loading the Initial Simulation
      The steady-state analysis runs are now complete. Set up the final transient run.
    - Selecting the Transient Calculation Physics Models
      Modify the physics model selections to activate the unsteady solver.
    - Setting the Solver Properties and Stopping Criteria
      Choosing the correct time-step is an important step in setting up an aeroacoustic simulation.
    - Visualizing the Mean Velocity
      Create a monitor for displaying the mean velocity magnitude in a scalar scene.
    - Monitoring Pressure
      Create three probes that are used to monitor pressure while the solvers are running.
    - Monitoring Force Coefficients
      By default Simcenter STAR-CCM+ provides a residuals plot which can be used to monitor the convergence of the solution.
    - Setting Up the Solution History File
      To save solution data at regular intervals while the simulation is running, you create a solution history file (.simh). In this tutorial, you save the pressure data on the cylinder wall and on the plane section, so that you can perform surface spectral analysis after the simulation completes.
    - Preparing the On-The-Fly FW-H Analysis
      The two key steps in preparing Simcenter STAR-CCM+ for a Ffowcs Williams-Hawkings analysis are to define the FW-H Surfaces and then define the FW-H Receivers. FW-H Receivers are points at specific distances from the noise sources.
    - Visualizing the Solution
      Add scenes for the noise emitted from the cylinder surface and received at each receiver.
    - Running the Simulation
      The simulation is now ready to be run. It is best that you run this simulation in parallel using several CPUs, as otherwise the run time is considerable.
    - Visualizing the Results
      You can now visualize the acoustic pressure on the cylinder, based on input from the two point-receivers.
    - Performing the Spectral Analysis
      Using Fast Fourier Transforms, you can determine sound pressure as a function of frequency at each of the point receivers.
    - Results Analysis
      Compare the peaks in the spectra with the Mesh Frequency Cutoff plot from the final steady-state simulation.
    - Summary
      This tutorial continued from the previous one, doing an unsteady analysis of the near field and an FW-H analysis of the far field.
    - DES and FW-H On-The-Fly Tutorial Bibliography
  - Ffowcs Williams-Hawkings: Sound Propagation
    This tutorial compares the Post FW-H model with the FW-H On-The-Fly model.
  - Signal Post-Processing: FFT and Wavenumber
    Several further analyses are possible using the simulation history file from the earlier tutorial, DES and FW-H On-The-Fly: Noise from a Cylinder (Unsteady Analysis). These analyses are covered in this tutorial.
  - Acoustic Wave Modeling: Noise from a Cylinder
    This tutorial demonstrates how to set up an acoustic wave simulation in Simcenter STAR-CCM+. The flow around a cylinder is used in the simulation to describe the required steps.
  - Lighthill Wave and Perturbed Convective Wave Modeling: Simplified HVAC Duct
    Noise generated by the air handling components in heating, ventilation, and air conditioning (HVAC) systems is a large contributor to interior cabin sound levels. Investigating the sources of noise and modifying the design accordingly, leads to better and quieter systems.
  - Sponge Layer Modeling: Simplified Tailpipe
    Unsteady aeroacoustics simulations require effective non-reflective boundary conditions to prevent spurious reflected acoustic waves from the boundaries of the computational domain interfering with the aeroacoustic results.
- Electromagnetism
  The following tutorials illustrate features for solving problems that involve electromagnetic fields.
- Electrochemistry
  The following tutorial demonstrates chemical reactions induced by an electrical current.
- Battery
  The tutorials in this set illustrate various Simcenter STAR-CCM+ features for setting up a battery model:
- Automation
  The tutorials in this set illustrate various Simcenter STAR-CCM+ automation and macro features.
- Design Exploration
  The tutorials in this set illustrate various features for running design exploration studies in Design Manager.
- Coupling with CAE Codes
  The tutorials in this set illustrate various Simcenter STAR-CCM+ features for coupling with CAE codes:
- Analysis Methods
  The tutorials in this set illustrate various Simcenter STAR-CCM+ features for analysing and visualizing simulation data.
- Simcenter STAR-CCM+ In-cylinder
  The tutorials in this set illustrate features for simulating internal combustion engines in Simcenter STAR-CCM+ using the dedicated add-on Simcenter STAR-CCM+ In-cylinder.

Results Analysis

Compare the peaks in the spectra with the Mesh Frequency Cutoff plot from the final steady-state simulation.

To analyze the results:

Open the simulation file for the steady-state calculation after 400 iterations (that is, the file cylinder.sim containing the refined mesh) alongside the existing cylinderUnsteady_FFT simulation.
In the same Simulation window, open the Scenes node.
Right-click Mesh Frequency Cutoff and select Open.
Select the Mesh Frequency Cutoff > Scalar 1 > Scalar Field node and set Max to 10000.

Use the mouse controls to obtain a plot similar to the following:

Compare the predicted spectra with the Mesh Frequency Cutoff plot from the steady-state simulation. You can see that there is a close correlation between the steady-state estimated cut-off frequency and the high-end frequency resolution from the DES calculation. All spectra show a change of gradient at ~6000 Hz. The change in gradient represents a change in the energy cascade to the higher frequencies, resulting artificially from inadequate resolution of the turbulent structures. These gradient kinks correspond with the fine-mesh steady-state Mesh Frequency Cutoff values local to those points. The spectral peak at ~500 Hz is the predicted vortex shedding frequency.

Many researchers (for example, Strouhal, Oertel, and Williamson, among others) have studied the sound that is generated by the flow around a circular cylinder.

Strouhal found that the frequency $f$ of the sound that is radiated from a cylinder of diameter $D$ is related to the free-stream velocity $U_{\infty}$ of a uniform flow. This relation is known as the Strouhal number $S t = f D / U_{\infty}$ . The Strouhal number is 0.2 to 0.22 for the Reynolds number range $300 \leq Re \leq 10^{4}$ (Inoue). For this case of a cylinder 20 mm in diameter and a free-stream air velocity of 50 m/s, the Reynolds number is 6.38 × 10⁴ and the Strouhal number is 0.2. The frequency $f$ of the sound is 500 Hz. This predicted frequency is identical to the shedding frequency of vortices behind the cylinder.

The SPL vs. frequency plot can numerically predict the frequency peak of 500 Hz generated by vortex shedding from the cylinder surface into its wake. This suggests that DES predicts the vortex shedding well and that the Strouhal number is close to the experimental value.

Save and close the simulation.