Anisotropic Thermal Conductivity for Multi-Part and Multi-Layer Solid

Anisotropic Thermal Conductivity for Multi-Part and Multi-Layer Solid

Problem Statement

A customer modeling anisotropic thermal conductivity in a composite panel skin layer using STAR-CCM+ multiphysics CFD code encountered a deprecated or legacy functionality when using a Multi-Part Solid or Multi-Layer Solid, as shown in the below figures, respectively.

Multi-Part and Multi-Solid Anisotropic Thermal Conductivity

The following warning message appears:
Warning: Anisotropic (Depricated/Legacy) material property method (used in Composite 2 for Thermal Conductivity) has been deprecated starting in Simcenter STAR-CCM+ 2210 and is planned to be removed in 2306. Please contact your Simcenter customer support representative for further information. 

How do you model solid anisotropic thermal conductivity in STAR-CCM+ using a Multi-Part Solid or Multi-Layer Solid?

Multi-Part Solid

The Anisotropic (Deprecated) physics allows a full matrix of 2x2 = 4 values in 2D & 3x3 = 9 values in 3D, and it has been argued that the full matrix does not conform to any real material and should instead be replaced by a symmetric specification method (3 values in 2D & 6 values in 3D), as shown in the below figure. 
      Multi-Part Solid Deprecated


This is why a new Anisotropic (6 components) material property specification method has been introduced for Thermal Conductivity, as shown in the below figure.

Multi-Part Solid Thermal Conductivity

Multi-Layer Solid

Anisotropic (6 component) will be available with Multi-Layer solid model in future versions. As a replacement, a new "Region Scalar Profile" material property specification method has been introduced for Thermal Conductivity material property which allows you to specify a scalar profile at Region > Physics Values level. You can specify thermal conductivity using different methods including Field Function, Table (x,y,z), User Code, etc. The same material property specification method is available for Multi-Part Solid.
                  

V2302 Documentation and Corrections

  1. Simulating Physics > Materials > Modeling Multi-Component Solids > Multi-Part Solid Model Reference
    1. If any material in the simulation has anisotropic thermal conductivity, create a dedicated physics continuum for that material. The Multi-Part Solid model does not currently support materials that require the Anisotropic method for Thermal Conductivity.
    2. The previous bullet listed in the documentation for v2302 has not been updated to reflect the actual functionality as confirmed with the development team. You may specify Anisotropic thermal conductivity for each part under the same Physics or Regions.
  2. Simulating Physics > Materials > Modeling Multi-Component Solids > Multi-Layer Solid Model Reference
    1. Effective Anisotropic Thermal Conductivity tensor:
      Effective Anisotropic Thermal Conductivity tensor
    2. This formula related to the Anisotropic (Deprecated) method is expected to be removed from User Guide.

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