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Thermal loads and constraints
Guidelines for defining thermal loads, temperature constraints, and controller-driven conditions in a simulation.
How to apply a spatially varying heat load on a polygon face?
This article explains how to apply a spatially varying heat input across a polygon face in a thermal solution.

Knowledge base articles
- Knowledge base articles
  This knowledge base provides concise, practical guidance for solving thermal, flow, multiphysics, space systems, and turbomachinery modeling challenges in Simcenter 3D. Each article provides you with step-by-step guidance, best practices, and tips to help you handle complex processes and use key features effectively.
- Model preparation
  Best practices for assembling and preparing simulation models.
- Thermal loads and constraints
  Guidelines for defining thermal loads, temperature constraints, and controller-driven conditions in a simulation.
  - How to define a thermostat based on a temperature difference between two elements?
    This article provides two methods for defining a thermostat based on a temperature difference between two elements.
  - How to use an average surface temperature as an input in expressions?
    To use the temperature of a solid as an input in expressions, you can use a function of the temperature at a specified point, TEMP(“point name”). However, Simcenter 3D does not have a specific function of the temperature on the surface to use in expressions. This article provides three alternative methods for using average surface temperature in expressions.
  - How to define a value in the boundary condition as a function of time?
    This article explains how to define a value for the boundary condition as a function of time, when the time points follow a complex formula.
  - How to set time-varying set point temperature for the PID active heater controller?
    This article explains how to set a time-varying set point temperature for the PID active heater controller.
  - How to constrain duct temperatures on nodes or elements in Simcenter 3D?
  - How to apply a spatially varying heat load on a polygon face?
    This article explains how to apply a spatially varying heat input across a polygon face in a thermal solution.
- Thermal couplings
  Methods and best practices for defining, verifying, and troubleshooting thermal couplings in the model.
- Solver and performance
  Procedures and recommendations for executing the thermal solver, managing restart workflows, and optimizing computational performance.
- Post-processing
  Techniques for reviewing results and interpreting thermal solver output.
- Troubleshooting
  Procedures for resolving solver errors, warnings, and convergence problems.
- Advanced thermal modeling
  Advanced methods for simulating complex thermal phenomena.
- Customization and plugins
  Guidance for developing plugins and custom tools to enhance thermal simulation workflows.
- Flow specific
  Flow specific knowledge base articles.
- Space systems specific
  Guidance for modeling spacecraft thermal environments, including multi-layer insulation (MLI), ablative materials, orbital heating, radiation modeling, and mission-specific boundary conditions.
- Turbomachinery specific
  Articles covering axisymmetric thermal modeling, bolt/nut interfaces, hybrid 2D–3D thermal mapping, thermal streams, voids, duct networks, and other turbomachinery-specific thermal workflows.
- FE model correlation and model update
  Model correlation and model update knowledge base articles, including how-to-guides, best practices, and troubleshooting tips.

How to apply a spatially varying heat load on a polygon face?

This article explains how to apply a spatially varying heat input across a polygon face in a thermal solution.

The thermal solver does not support spatially varying heat loads in watts because such loads are non-conservative. This means:

The applied energy would depend on the mesh density.
The solution may produce inaccurate or inconsistent energy balance.
The results could vary depending on how finely the face is meshed.

Use a spatially varying heat flux in W/m² instead. A heat flux is a conservative quantity, meaning the total applied energy is independent of the mesh resolution.

To apply a spatially varying heat flux on a polygon face, you can:

Create a data file, such as a CSV or text file containing the heat flux values at specific coordinate locations on the polygon face.
Create a new thermal load using the Heat Flux type and select the polygon face where the spatially varying heat flux will be applied.
In the Magnitude group, select New Field→Table.
In the Independent Domain page, choose Cartesian and in the Definition page, import the field data to define the heat flux distribution over that face.