IotaSuite User Manual
  • Summary
  • Dashboard
    • Creating a Project
    • Editing a Project
    • Deleting a Project
    • Loading a Project
    • Unloading a Project
  • Project
    • Datasets
      • Importing a Dataset
      • Editing a Dataset
      • Deleting a Dataset
      • Visualising a Dataset
    • Screenshots
      • Importing a Screenshot
      • Editing a Screenshot
      • Deleting a Screenshot
      • Exporting a Screenshot
    • Graphs
      • Importing a Graph
      • Editing a Graph
      • Deleting a Graph
      • Exporting a Graph
    • Meshes
      • Importing a Mesh
      • Editing a Mesh
      • Deleting a Mesh
    • Videos
      • Editing a Video
      • Deleting a Video
      • Exporting a Video
    • Files
      • Importing a File
      • Editing a File
      • Deleting a File
    • Scripts
      • Importing a Script
      • Editing a Script
      • Deleting a Script
    • List of Scenarios
      • Creating a New Scenario
      • Loading a Scenario
      • Deleting a Scenario
      • Cloning a Scenario
  • Scenario
    • Creating a New scenario
    • Loading a Scenario
    • Editing a Scenario
    • Deleting a Scenario
    • Cloning a Scenario
  • Pre
    • Cretaing a Mesh of a Simple Geometry
      • Circle
      • Rectangle
      • Cuboid
      • Cylinder
    • Loading a Mesh
    • Importing a Mesh from a File
    • Filling holes of a Surface Mesh
    • Generating / Re-meshing a volume mesh
    • Remeshing a surface mesh
    • Creating Cut-Planes
  • Post
    • Visualising Results
    • Animating Results
    • Taking a Screenshot
    • Recording an Animation
    • Setting a View
      • Exporting and Importing a View
    • Post-processing Tools
      • Generating Cut Planes with Results
      • Generating a Line Variation Graph
      • Generating a Point Evolution Graph
      • Generating a Result Integral Graph
      • Generating a Result Statistics Graph
  • Graph
    • Customizing the Style of a Graph Traces
    • Customizing Graph Axes Settings
    • Exporting a Graph as an Image
  • Coarse-graining
    • Introduction
    • Coarse-granining module
      • Loading a Mesh
      • Input
        • Input DEM data
          • EDEM 2017+
          • LIGGGHTS-DUMP
          • LIGGGHTS-VTK
          • P4X
        • Pre-Filters
          • Overwrite Groups by Size
          • Filter Group ID
          • Filter by Bounding Box
          • Overwrite Velocity
          • Overwrite Groups
      • Averaging
        • Temporal Averaging
        • Spatial Averaging
          • Function
          • Width and Cutoff Factor
          • Gradients
          • Spatial Integral
        • Advanced
          • Particle Group Concentration
          • Surface/Wall Analysis
          • Residence Time
      • Output
        • Scale Results
        • Create DEM Dataset
        • Coarse Graining Output
        • Output Cylindrical Coordinates
        • Post-Analysis
          • Mixing
          • User-defined Scripts
  • Using Iota with EDEM
  • Using Iota with LIGGGHTS
    • LIGGGHTS-DUMP
    • LIGGGHTS-VTK
  • Using Iota with ANSYS-Fluent
  • Tutorials
    • Backhoe Tutorial EDEM 2017+
    • Paddle Mixer Tutorial EDEM 2017+
  • Licensing
    • Iota-Suite End User Agreement
    • Third Party Licenses
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Coarse-graining

PreviousExporting a Graph as an ImageNextIntroduction

Last updated 5 years ago

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In most cases where the is used, it is necessary to carry out some averaging of the data to a scale more representative of what is required. As such it is quite common for spatial averaging, temporal averaging, or both, to be applied to the DEM data. To aid the process, a module for the processing of DEM data both temporally and spatially has been implemented in Iota. The module provides both a coarse graining method to calculate bulk quantities and project those onto a continuum field. Some of the results are shown in .

The coarse-grained density ρ is provided by equation:

where

  • r is a point in space where the values are to be evaluated,

  • ri(t) is a vector to the centre of mass of the ith particle at a given timestep t,

  • mi is that particle's mass, and

The coarse-grained velocity V is provided from equation

where p is the coarse-grained momentum density:

where vi(t) is the particle's velocity vector.

The stress tensor is given by equation:

where fijα is the interaction force between two particles, rijβ is the branch vector, s is the integral of the branch vector and v' is the fluctuating velocity of the particle.

Figure 50 - Iota-post toolbox in use - Post-processing on a fluidized bed. a) Particles visualization. b) Spatial averaged density. c) Spatial and temporal averaged density over 20 sec.

ϕ is the coarse-graining or which is subject to the condition of its integral over space being unity.

spatial averaging function
Discrete Element Method (DEM)
Figure 50
Coarse-grained density
Coarse-grained velocity
Stress tensor