# Solid Model

Volume Mesh Workflow Only

The Solid model is only available in the volume mesh workflow. It cannot be used with the surface mesh workflow.

The Solid model is used for setting up conjugate heat transfer volume models that contain all the common fields every heat transfer zone should have. This model is essential for simulating heat transfer in solid materials within the Flow360 simulation environment.

# 📋 Available Options

Option Description Unit
name Optional name identifier for the Solid model
entities List of volume entities where heat transfer equations will be solved
material Material properties of the solid thermal conductivity (e.g., W/m·K), density (e.g., kg/m³), specific heat capacity (e.g., J/kg·K)
heat_equation_solver Settings for the heat equation solver. See Heat Equation Solver documentation for details.
volumetric_heat_source Heat source per unit volume power per volume (e.g., W/m³)
initial_condition Initial temperature condition for the heat equation temperature (e.g., K)

# 🔍 Detailed Descriptions

# name

An optional identifier for the Solid model instance.

  • Default: None
  • Example: "solid_block"
  • Notes: Used for identification and reference purposes.

# entities

List of volume entities where the heat transfer equation will be solved.

  • Default: Required field
  • Example: [volume_mesh["solid-*"]]
  • Notes: Accepts volume mesh entities or patterns matching multiple volumes.

# material

Material properties of the solid, defining thermal characteristics.

  • Default: Required field
  • Example: See Python example below
  • Notes: Must specify thermal conductivity, density, and specific heat capacity.

# heat_equation_solver

Configuration for the heat equation solver settings. See Heat Equation Solver documentation for details.

  • Default: See Heat Equation Solver for default values
  • Example: See Python example below
  • Notes: Controls solver parameters like tolerance and iteration limits.

# volumetric_heat_source

Specifies the heat source per unit volume in the solid.

  • Default: 0 W/m³
  • Example: 1.0 * fl.u.W / fl.u.m**3
  • Notes: Can be a constant value or a string expression.

# initial_condition

Initial temperature condition for the heat equation solver.

  • Default: For unsteady: required, For steady: None
  • Example: HeatEquationInitialCondition(temperature="1.0")
  • Notes:
    • Can be specified using expressions for spatial variation
    • Required for unsteady simulations
    • Optional for steady simulations (will use a default uniform temperature field if not specified)

💡 Tips
  • Ensure all material properties are specified in consistent units.
  • When using patterns in entities, verify all matched volumes are intended for heat transfer simulation.
  • Consider mesh resolution near areas with high temperature gradients.
  • For conjugate heat transfer, ensure proper interface matching with fluid regions.

❓ Frequently Asked Questions

  • What happens if I don't specify an initial condition?

    For steady simulations, the solver will use a default uniform temperature field. For unsteady simulations, an initial condition must be specified.

  • Can I simulate multiple solid materials?

    Yes, create multiple Solid model instances with different materials and assign them to different volumes.

🐍 Python Example Usage

Below is a Python code example showing how to configure a Solid model for conjugate heat transfer:

# Define a Solid model for volumes with the name pattern "solid-*"
solid_model = fl.Solid(
    entities=[volume_mesh["solid-*"]],
    heat_equation_solver=fl.HeatEquationSolver(
        equation_evaluation_frequency=2,
        linear_solver=fl.LinearSolver(
            absolute_tolerance=1e-10,
            max_iterations=50
        ),
        relative_tolerance=0.001,
    ),
    initial_condition=fl.HeatEquationInitialCondition(temperature="1.0"),
    material=fl.SolidMaterial(
        name="aluminum",
        thermal_conductivity=235 * fl.u.kg / fl.u.s**3 * fl.u.m / fl.u.K,
        density=2710 * fl.u.kg / fl.u.m**3,
        specific_heat_capacity=903 * fl.u.m**2 / fl.u.s**2 / fl.u.K,
    ),
    volumetric_heat_source=1.0 * fl.u.W / fl.u.m**3,
)

← Heat Equation Solver →