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Post-Processing
Simcenter STAR-CCM+ allows you to post-process the solution after each iteration or time-step, (while the simulation is running), as well as when the simulation completes. For this reason, you generally create post-processing objects before running the simulation. Post-processing objects are also known as analysis objects.
Signal Processing
Signal processing applies data set functions to sets of wave data.
Post-Processing Data Set Functions
Simcenter STAR-CCM+ allows you to visualize Fourier transforms and surface spectra.
Post-Processing Surface Spectra
The process of setting up the post-processing of surface spectra involves several steps. The .trn file is used to display data set functions. Fourier Transform (FT) field functions are used to analyze the data.
Exporting Surface Spectral Data
To export surface spectral data, from the menu bar select File > Auto Export... opening the Auto Export dialog.

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Post-Processing
Simcenter STAR-CCM+ allows you to post-process the solution after each iteration or time-step, (while the simulation is running), as well as when the simulation completes. For this reason, you generally create post-processing objects before running the simulation. Post-processing objects are also known as analysis objects.
- Analysis Workflow
  The key steps in successfully analyzing simulation results are to: (1) be clear on what quantities you want to extract; (2) locate or define surfaces on which to obtain the data; and, (3) present the data in visual scenes or numeric output.
- Data Interpolation
  Most visualization objects such as plots, reports, and scalar displayers allow for smooth and non-smooth values. For example, the contour style for scalar displayers provides a Smooth Filled option (smooth) and a Filled option (non-smooth). The way these values are calculated depends on the discretization method.
- Field Function Interpolation and Interfaces (FV)
  For finite volume meshes, understanding how Simcenter STAR-CCM+ deals with field function data is important for avoiding non-physical results in post-processing at an interface, and to appreciate the difference that smoothing makes when it is applied.
- Accessing Solution Data through Derived Parts
  Although Simcenter STAR-CCM+ can display, analyze, and report simulation data on regions, boundaries, and parts, there are many cases when you want to access data in other entities of the solution space. Derived parts provide a mechanism for defining additional entities on which you can access solution data.
- Visualizing the Solution
  The visualization tools in Simcenter STAR-CCM+ are integrated with the analysis, allowing for the interactive extraction and viewing of solution data from either a running or converged simulation.
- Transient Solution Data
  For transient solutions, Simcenter STAR-CCM+ provides the simulation history file (.simh) to which you can save selected data while a simulation is running. After the simulation completes, you can load this file and query its states for post-processing.
- Sampling Data Values Using Reports and Monitors
  This workflow incorporates the roles of both reports and monitors.
- Accessing Field Data from Previous Time-Steps or Iterations
  A field history is a type of field monitor that stores a finite number of past values (or samples) of a field function, captured at moments defined by its update policy, for a given set of input regions or boundaries (or both).
- Reporting Results
  Reports provide summaries of solution data.
- Monitoring the Solution
  Monitors sample, save, and plot solution data.
- Plots
  The plotting features in Simcenter STAR-CCM+ allow you to create three kinds of two-dimensional plots.
- Exploring Solutions with Data Focus
  This interactive tool lets you extract knowledge of merit -- information that facilitates a correct engineering decision -- from a large volume of data.
- Parametric Positioning for Analysis Surfaces in Turbomachine Domains
  In studies of cases of revolving volumes, such as turbomachinery, a typical requirement for post-processing is to render and plot data on surfaces or profiles that are positioned parametrically in relation to the domain bounding surfaces. For example, you may wish to view the total pressure on a surface located exactly half-way between the hub and shroud, or you may wish to plot pressure across both blade surfaces on a given slice.
- Triggers and Update Events
  Several features of Simcenter STAR-CCM+ require that you define a trigger for when an action takes place. Simcenter STAR-CCM+ provides three built-in trigger types, and one custom trigger type (defined by an update event).
- Signal Processing
  Signal processing applies data set functions to sets of wave data.
  - Signal Processing Concepts
    Signals can be expressed as oscillating changes of signal strength over time or as a function of signal strength over a range of frequencies. Both methods have their uses. Information can be converted from one form to the other by Fourier transforms.
  - Creating Data Set Functions
    To add a data set function, right-click the Data Set Functions node and select a type from the New submenu of the pop-up menu.
  - Point Time Histories
    Point Time Histories are time histories at a point in the input signal which are then processed using a Fourier transform.
  - Point Time Fourier Transforms
    Point Time Fourier Transforms are Fourier transforms for one time point in the input signal.
  - Point-to-Point Time Fourier Transforms
    You use Point-to-Point Time Fourier transforms to determine the correlation between two input signals. This data set function applies a Fourier transform to each of the input signals, then performs a convolution on both resulting transforms.
  - Point-to-Point Time Correlations
    You use Point-To-Point Time correlations to determine the phase differences between the dominant modes of two input signals.
  - Point Inverse Time Fourier Transforms
    This inverse transform allows data to be transformed from the frequency to the time domain.
  - Line Time Histories
    A Line Time History is a collection of Point Time Histories that are drawn from the points that make up a line probe.
  - Line Time Fourier Transforms
    Line Time Fourier Transforms let you calculate Fourier transforms at various point along a line probe.
  - Line Spatial Fourier Transforms
    Line Spatial Fourier Transforms allows the creation of a matrix of energy densities dependent on wavenumber and frequency along a line probe.
  - Surface Time Histories
    A Surface Time History is a collection of Point Time Histories that are drawn from the points that make up a presentation grid.
  - Surface Time Fourier Transforms
    Surface Time Fourier Transforms let you calculate Fourier transforms at various point within a presentation grid.
  - Line Time Domain Filter
    You can use Line Time Domain filters to create frequency-band filtered line time histories, which is similar to carrying out inverse line FFT. Using filtered line time histories enables you to visualize flow quantitites in a specified frequency range, which can be useful for identifying and analyzing periodic flow structures or time harmonic phenomena such as acoustic waves. Line Time Domain filtering can only be carried out on scalar quantities saved in .trn files.
  - Surface Time Domain Filter
    You can use Surface Time Domain filters to create frequency-band filtered surface time histories, which is similar to carrying out inverse surface FFT. Using filtered surface time histories enables you to visualize flow quantitites in a specified frequency range, which can be useful for identifying and analyzing periodic flow structures or time harmonic phenomena such as acoustic waves. Surface Time Domain filtering can only be carried out on scalar quantities saved in .trn files.
  - Exporting Filtered Time History Fields
    You can export filtered time history field data as a Matlab .mat file.
  - Derived Data
    Derived data objects allow a data set function to access data from various other objects in the simulation, as well as from external files.
  - Post-Processing Data Set Functions
    Simcenter STAR-CCM+ allows you to visualize Fourier transforms and surface spectra.
    - Plotting Fourier Transforms
      You can plot a Fourier transform from a monitor containing periodic data.
    - Setting the Transform Plot Properties of Data Sets
      You can set the plot properties of a Line Time, Line Spatial, or Surface Time Fourier Transform using the Output Control node.
    - Post-Processing Surface Spectra
      The process of setting up the post-processing of surface spectra involves several steps. The .trn file is used to display data set functions. Fourier Transform (FT) field functions are used to analyze the data.
      - Exporting Surface Spectral Data
        To export surface spectral data, from the menu bar select File > Auto Export... opening the Auto Export dialog.
      - Importing Surface Spectral Data
        To import surface spectral data, from the menu bar select File > Import > Import CAE Model... and navigate to the generated .trn file.
      - Working with Surface Spectra Field Functions
      - Selecting Units for FT Field Functions
        Simcenter STAR-CCM+ calculates the dimensions for the FT field functions and provides a list of suggested units that are based on these dimensions.
      - Using the Display Time
        Display time is controlled from a slider on the transient model, which updates the scene automatically.
      - Extracting the F-X Spectra Using a Line Probe
        Spectra contours give useful clues on the dominant frequencies in a problem. To visualize spectra contours, export data from on a plane section, then, in post-processing, position a line probe on the plane in different locations.
  - Pop-Up Menu of the Data Set Functions Manager
  - Data Set Functions Formulation

Exporting Surface Spectral Data

To export surface spectral data, from the menu bar select File > Auto Export... opening the Auto Export dialog.

The available property settings are detailed below:

Trigger Type -- The .trn file can be exported for any transient case setting, with the following options available:
- Iterations -- Data is exported every n iterations, where n is specified in the Frequency property.
- Time Steps -- Data is exported every n time steps, where n is specified in the Frequency property.
- Delta Time -- Data is exported as defined by the Delta Time property.
Enabled -- Must be activated in this instance, to allow the auto export of data.
Base Name -- The file name of the .trn file.
Frequency -- Specifies the number of Iterations or Time Steps between the exports. Neglected if Delta Time is set as the Trigger Type.
Delta Time -- Specifies the duration of solution time between exports. Neglected if Iterations or Time Steps is set as the Trigger Type.
Export Directory -- The directory to which the .trn file is exported.
File Format -- Must be set to Surface fft files (*.trn).
Append to File -- Must be activated to add data to the file defined by the Base Name and Export Directory properties.
Export Solution Data Only -- If activated the mesh is exported once only. Therefore, effects such as a moving mesh are not captured.
Scalar Functions -- Define the scalar functions to export.
Vector Functions -- Define the vector functions to export.
Regions -- Neglected when exporting to a .trn file.
Boundaries -- Define the boundaries to export.
Derived Parts -- Define the derived parts to export.

When the case is run, a .trn file is generated, which can then be imported.