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Physics Simulation
Simcenter STAR-CCM+ can model a wide range of physics phenomena including fluid mechanics, solid mechanics, heat transfer, electromagnetism, and chemical reactions. Scenarios with multiple time scales can be solved within the same simulation.
Electromagnetism
Simcenter STAR-CCM+ allows you to model engineering applications involving electromagnetic phenomena. Example applications are electric motors, electric switches, and transformers, which can be modeled based on the classical theory of Electromagnetism.
Modeling Electric Currents
The following steps outline the recommended workflow for modeling electric currents in conducting media.
Defining Boundary and Interface Conditions
To allow the current to enter and leave the domain, set the electric potential or specific electric current at the “inlets” and “outlets” to the electrified domain, for example at the terminals. The current density is considered to be solenoidal, which is equivalent to an incompressibility condition for fluids. Therefore, the amount of current going into the domain is the same as the current leaving it.
Setting the Electric Current Potential Characteristic
For some engineering applications, it is of interest to prescribe a characteristic relation of electric current to electric potential drop at a boundary or an interface. This characteristic relation can also be known as the potential-voltage characteristic or polarization curve.

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Physics Simulation
Simcenter STAR-CCM+ can model a wide range of physics phenomena including fluid mechanics, solid mechanics, heat transfer, electromagnetism, and chemical reactions. Scenarios with multiple time scales can be solved within the same simulation.
- Defining Physics Workflow
  Simcenter STAR-CCM+ contains a wide range of physics models and methods for the simulation of single- and multi-phase fluid flow, heat transfer, turbulence, solid stress, dynamic fluid body interaction, aeroacoustics, and related phenomena. These physics models are all selected using a physics continuum.
- Setting Up Physics
  This section provides information on how to set up physics models in STAR-CCM+.
- Running Physics Simulations
  This part of the documentation describes preparation and procedures for running a Simcenter STAR-CCM+ simulation.
- Motion
  In general, motion can be defined as the change in position of a body with respect to a certain reference frame.
- Space
  The primary function of the Space models in Simcenter STAR-CCM+ is to provide methods for computing and accessing mesh metrics. Examples of mesh metrics include cell volume and centroid, face area and centroid, cell and face indexes, and skewness angle.
- Time
  The primary function of the time models in Simcenter STAR-CCM+ is to provide solvers that control the iteration and/or unsteady time-stepping.
- Mesh Motion and Adaption
  Many simulations that involve motion or geometry change require you to move or deform the mesh. Other simulations require localized mesh adaption in order to achieve an accurate solution.
- Materials
  Material models simulate substances, including various mixtures.
- Fluid Flow
  Many engineering design projects require you to predict the effect of flowing fluids on containing structures or immersed objects. While you can analyse simple scenarios with hand calculations, complex scenarios require you to apply numerical methods for accurate solutions.
- Viscous Flow
  Viscous Flow is a finite element approach for use with viscoelastic materials and other highly viscous non-Newtonian fluids, such as liquid plastics and rubber, dough and similar foodstuffs, molten glass, and mud. Viscoelastic materials resemble elastic materials, but also exhibit viscous effects, rebounding slowly from deformations.
- Passive Scalars
  Passive scalars are user-defined variables of arbitrary value, assigned to fluid phases or individual particles. They are passive because they do not affect the physical properties of the simulation. An intuitive way to think of passive scalars is as tracer dye in a fluid, but with numerical values instead of colors, and with no appreciable mass or volume.
- Heat Transfer
  Heat transfer is the study of energy in transit due to a temperature difference in a medium or between media. Heat transfer extends thermodynamic analysis through the study of the modes of energy transfer and through development of relations to calculate energy transfer rates.
- Species
  This chapter provides information about the chemical species models in Simcenter STAR-CCM+. A species model is activated whenever a multi-component liquid or multi-component gas is chosen from the Material model section of the Physics Model Selection dialog.
- Porous Media
  Simcenter STAR-CCM+ allows you to simulate the transport of a fluid or energy (e.g. heat, electrical charge) through porous materials using the concept that the action of the porous media can be represented using appropriate loss (or 'diffusion') coefficients.
- Adjoint
  The adjoint method is an efficient means to predict the influence of many design parameters and physical inputs on some engineering quantity of interest, that is, on the engineering objective of the simulation. In other words, it provides the sensitivity of the objective (output) with respect to the design variables (input).
- Fans and Blowers
  Simcenter STAR-CCM+ provides models for axial and radial fans where classical fan laws apply.
- Virtual Disk Model
  The virtual disk model is based upon the principle of representing propellers, turbines, rotors, fans, and so on, as an actuator disk. The actuator disk treatment is practical when you are concerned about the influence of the rotor/propeller behavior on the flow rather than knowing about the detailed interactions between the flow and the blades of the rotating device.
- Turbulence
  Most fluid flows of engineering interest are characterized by irregularly fluctuating flow quantities.
- Transition
  The term transition refers to the phenomenon of laminar to turbulence transition in boundary layers. A transition model in combination with a turbulence model predicts the onset of transition in a turbulent boundary layer.
- Wall Distance
  Wall distance is a parameter that represents the distance from a cell centroid to the nearest wall face with a non-slip boundary condition. Various physical models require this parameter to account for near-wall effects.
- Radiation
  The Radiation Model is the gateway, or entry point to all of the radiation modeling capabilities of Simcenter STAR-CCM+. This section describes Simcenter STAR-CCM+’s radiation modeling.
- Aeroacoustics
  Aeroacoustics investigates the aerodynamic generation of sound.
- Reacting Flow
  Simcenter STAR-CCM+ provides a selection of models that you can use to simulate a wide range of reacting flow applications.
- Internal Combustion Engines
  In an internal combustion engine (ICE), for example a gasoline engine, the process of combustion takes place in a cylinder (or cylinders) within the engine. The working fluid is a fuel and oxidizer mixture (usually air), which reacts to form combustion products.
- Multiphase Flow
  Multiphase flow is a term which refers to the flow and interaction of several phases within the same system where distinct interfaces exist between the phases. Simcenter STAR-CCM+ considers flow options where phases coexist as: gas bubbles in liquid, liquid droplets in gas, and/or solid particles in gas or liquid, and/or (large scale) free surface flows.
- Dynamic Fluid Body Interaction
  Dynamic Fluid Body Interaction (DFBI) in Simcenter STAR-CCM+ allows you to simulate the motion of a 6-DOF body with the displacement and rotation resulting from the defined mechanical and multiphysics interaction (flow, DEM, solid stress, EMAG).
- Harmonic Balance
  Some unsteady flows have a regularly repeating flow pattern, that is, they are time-periodic. Consider the flow from a fan blade passing across the entrance to a duct. Measurements of the instantaneous flow just within the duct would show a regularly repeating pattern. If the flow disturbances are sufficiently large, and propagate to the end of the duct, measurements of the unsteady flow at any point within the duct show repeating patterns. Such time-periodic patterns can be expressed using Fourier series.
- Solid Stress
  Simcenter STAR-CCM+ allows you to model the response of a solid continuum to applied loads, including mechanical loads and thermal loads that result from changes in the solid temperature.
- Electromagnetism
  Simcenter STAR-CCM+ allows you to model engineering applications involving electromagnetic phenomena. Example applications are electric motors, electric switches, and transformers, which can be modeled based on the classical theory of Electromagnetism.
  - Modeling Electrostatics
    The following steps show how to model electric fields induced by static or quasi-static distributions of electric charges.
  - Modeling Electric Currents
    The following steps outline the recommended workflow for modeling electric currents in conducting media.
    - Selecting the Physics Models and Materials
      The Electrodynamic Potential model solves for the electric potential to calculate the electric field and the electric current density.
    - Defining the Electrical Conductivity
      When modeling electric currents in conducting materials, you specify the material electrical conductivity $σ$ , which defines the relationship between the electric current density $J$ and the electric field $E$ according to Ohm's law.
    - Setting the Transfer Current Density
      The Transfer Current Density $S$ is a user-specified contribution to the electric current within a specified region.
    - Setting the Electromotive Force Density
      The Electromotive Force Density $ρ_{ϵ}$ is a user-specified contribution to the electric field within a specified region.
    - Defining Boundary and Interface Conditions
      To allow the current to enter and leave the domain, set the electric potential or specific electric current at the “inlets” and “outlets” to the electrified domain, for example at the terminals. The current density is considered to be solenoidal, which is equivalent to an incompressibility condition for fluids. Therefore, the amount of current going into the domain is the same as the current leaving it.
      - Setting the Electric Current Potential Characteristic
        For some engineering applications, it is of interest to prescribe a characteristic relation of electric current to electric potential drop at a boundary or an interface. This characteristic relation can also be known as the potential-voltage characteristic or polarization curve.
  - Modeling Magnetic Fields
    The following steps outline the recommended workflow for modeling magnetic fields induced by electric currents, excitation coils, and permanent magnets.
  - Modeling Ohmic Heating
    Simcenter STAR-CCM+ allows you to calculate the heat that is generated by electric currents flowing in resistive materials. You can use the Ohmic Heating model in combination with an energy model.
  - Modeling Magnetohydrodynamics (MHD)
    In electromagnetic applications involving electrically conducting fluids, such as molten metals, electrolytes, and plasmas, Simcenter STAR-CCM+ allows you to account for the interaction between the conducting fluid and the magnetic field.
  - Airgap Remeshing
    Electromagnetic simulations require a conformal mesh across all interfaces. In simulations that involve regions in relative motion, you can keep the mesh conformal at every time-step using the airgap remeshing technique. With this technique, Simcenter STAR-CCM+ keeps the mesh conformal by regenerating the mesh near the sliding interface in every time-step.
  - Physics Models Reference
  - Using the Circuit Model
    The Circuit model lets you model a circuit with specified circuit elements and circuit connections. Selecting this model activates the circuit solver in the physics continuum.
  - Accessing Electromagnetism Constants through the Java API
    The Java API defines several compile-time constant expressions, which are common for electrodynamics. These constants can be accessed in a Java macro.
  - Troubleshooting
    This section contains troubleshooting information.
- Electrochemistry
  Electrochemistry is the study of chemical reactions which occur due to an imposed electrical charge, or a difference in electrical potential at a boundary between a conductor–such as a metal–and an electrolyte. Simcenter STAR-CCM+ provides models that allow you to simulate batteries, corrosion, etching, and other electrochemical reactions.
- Electric Circuits
  Electrical circuits are conducting loops of interconnected electrical components, such as batteries, power sources, resistors, and inductors.
- Plasma
  Plasma is a state of matter similar to a gas that is composed partially or completely of charged particles such as ions and electrons which are not bound to each other.
- Batteries
  You can simulate batteries in Simcenter STAR-CCM+ using battery cells and battery cycling procedures that are defined either directly in Simcenter STAR-CCM+, or in the external software package Simcenter Battery Design Studio.
- Casting
  Casting simulations are performed using transient multiphase simulations using the VOF model with solidification. Conjugate heat transfer is applied between the solidifying melt and the solid mold.
- Region Sources
  This section provides some guidelines on how to use region sources for some common problems.
- Cell Quality Remediation
  The Cell Quality Remediation model helps you get solutions on a poor-quality mesh. This model identifies poor-quality cells, using a set of predefined criteria, such as Skewness Angle exceeding a certain threshold. Once these cells and their neighbors have been marked, the computed gradients in these cells are modified in such a way as to improve the robustness of the solution.
- Guidelines for Applying Simcenter STAR-CCM+
  This part of the documentation provides guidelines on applying Simcenter STAR-CCM+ models to your applications.
- Common Solvers Reference
  In Simcenter STAR-CCM+, solvers compute the solution during the simulation run.

Setting the Electric Current Potential Characteristic

For some engineering applications, it is of interest to prescribe a characteristic relation of electric current to electric potential drop at a boundary or an interface. This characteristic relation can also be known as the potential-voltage characteristic or polarization curve.

Example applications where it is convenient to define the I-V characteristic at boundaries are:

cathodic protection, in which the complexity of the electro-chemical corrosion process is reduced to the polarization curve of a specific setup
diodes
photovoltaic elements
electron/ion emission into plasmas

You can specify an Electric Current Potential Characteristic condition at boundaries and contact interfaces when the Electrodynamic Potential Model is selected. For example:

Select the [Region] > Boundaries > [Boundary] > Physics Conditions > Electric Potential Specification node and set the Method to Electric Current Potential Characteristic.
Select the [Region] > Boundaries > [Boundary] > Physics Values > Current Voltage Characteristic node and in the Properties window, set Method to one of the following options:
- Butler-Volmer (Butler-Volmer Current-Potential Characteristic)
- Tabular Polarization Curve

Using the Butler-Volmer Method

When using the Butler-Volmer method, you specify the quantities that appear in the Butler-Volmer equation (see Eqn. (4296)) by setting the corresponding properties. See Current Voltage Characteristic Properties.

Using the Tabular Polarization Curve Method

The relationship between the specific electric current,

j_{n}

, and the potential drop across the boundary or interface,

ϕ_{1} - ϕ_{0}

is specified using tabular data. See Tabular Polarization Curve Properties.

Select the [Region] > Boundaries > [Boundary] > Physics Values > Current Voltage Characteristic > Tabular Polarization Curve node and set the appropriate Tabular Polarization Curve Properties.
Select the Tabular Polarization Curve > Table Sorting node and specify the Option.
The Table Sorting Option is set to Electric Potential by default, which is appropriate for most applications. However, if you are setting up a plasma simulation with non-monotonic current voltage characteristics, you can select Specific Electric Current. See Table Sorting Properties.