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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.
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.
Maintaining the Appropriate Acoustic CFL in the Wave Equation
To maintain the accuracy of acoustic predictions, apply criteria for points per wavelength (PPW) and the Acoustic CFL. This section outlines the requirements and calculations for this case.

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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.
  - 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.
    - Prerequisites
      The instructions in the Acoustic Wave Solver tutorial assume that you are already familiar with certain techniques in Simcenter STAR-CCM+.
    - Loading the Base Simulation
      A base simulation file has been prepared for this analysis. Continue by starting the simulation, loading the base simulation file, and saving it under a new file name.
    - Maintaining the Appropriate Acoustic CFL in the Wave Equation
      To maintain the accuracy of acoustic predictions, apply criteria for points per wavelength (PPW) and the Acoustic CFL. This section outlines the requirements and calculations for this case.
    - Generating the Volume Mesh
      The meshing models and mesh reference values for this simulation have already been set up. A volumetric control has been created for mesh refinement, to capture the separation behind the cylinder, and to capture the vortex shedding.
    - Obtaining a Steady Solution
      Run a steady turbulent simulation to get an initial flow solution. This solution is used as a starting point for the unsteady simulation.
    - Obtaining an Unsteady Solution
      Starting from the solution of the steady simulation, perform an unsteady simulation until the flow reaches a fully developed state.
    - Obtaining the Acoustic Wave Solution
      Starting from the solution of the unsteady simulation (a fully developed flow solution), activate the Acoustic Wave model, specify the noise source region, and then run the simulation to compute the acoustic pressure.
    - Summary
      This tutorial demonstrated how to set up an acoustic wave simulation in Simcenter STAR-CCM+, using the flow around a cylinder.
  - 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.

Maintaining the Appropriate Acoustic CFL in the Wave Equation

To maintain the accuracy of acoustic predictions, apply criteria for points per wavelength (PPW) and the Acoustic CFL. This section outlines the requirements and calculations for this case.

The mesh size in the acoustic zone affects two criteria that are important for accurate acoustic predictions: the Acoustic CFL and the points per wavelength (PPW). The appropriate calculations for this tutorial are shown below.

Points Per Wavelength (PPW)

The recommended PPW for an acoustic calculation is PPW ≥ 30-40, maintained throughout the undamped zone. You can calculate the expected wavelength for this simulation from the vortex shedding frequency across the cylinder. This frequency is calculated from the Strouhal number:

S t = \frac{f D}{v}

(5266)

where $f$ is the vortex shedding frequency, $D$ is the diameter of the cylinder, and $v$ is the air velocity.

The settings given in this tutorial are representative for a typical industrial application, where flow is turbulent.

The Reynolds number for this tutorial is $Re = 6.38 \cdot 10^{4}$ , which is within the sub-critical range $300 < Re \leq 1.5 \cdot 10^{5}$ . To obtain the correct vortex shedding frequency it would be necessary to use the Laminar model instead, according to the flow regime that the cylinder experiences.

The expected Strouhal number for this regime is $S t = 0.2$ , which corresponds to a frequency of:

f = S t \frac{v}{D} = 0.2 \cdot 50 / 0.02 = 500 H z

The wavelength in turn is calculated as:

λ = c / f

where $c = 340 m / s$ is the speed of sound. As $P P W = (c / f) / Δ x$ , the required mesh size for PPW of 40 is:

Δ x = \frac{340 \frac{m}{s} / 500 \frac{1}{s}}{40} = 0.017 m

Acoustic CFL

For the recommended PPW of 40, aim to have Acoustic CFL ≤ 4 in the zone of interest. Acoustic CFL is defined as:

Acoustic CFL = c \frac{Δ t}{Δ x}

(5267)

Rearranging and inserting a time-step $Δ t$ of $2.5 \cdot 10^{- 5} s$ gives a candidate mesh size of:

Δ x = 340 \frac{m}{s} \cdot (2.5 \cdot 10^{- 5} s) / 4 = 0.002125 m

Overall Mesh Size

Taking the lower computed amount of 0.002125 m and rounding down gives a final target mesh size of 0.002 m in the acoustic zone.