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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.
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.
Working With the Casting Material Database
The accuracy of a casting simulation depends on the quality and completeness of the material data that you use. Therefore, a database that contains certified and qualified property data for casting is essential for high quality casting simulations.
Working with User-Defined Data
Within the Casting Material Database, a user-defined material database allows you to run casting simulations with your own material data.

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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.
- 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.
  - Selecting the Physics Models for the Melt
    You select the multiphase models, a laminar flow regime, and the casting model.
  - Selecting the Physics Models for the Mold
    The mold is a solid material. To investigate the heat transfer in the mold, you activate the solution of the energy equation in the solid. Optionally, you can take radiation into account.
  - Selecting the Pure Thermal Model
    A pure thermal simulation simulates only the solidification process of the melt. The solution of the flow equations is de-activated and only the solution of the energy equation is activated. This simulation type lets you analyze the behavior of the solidifying melt with respect to temperature without any flow.
  - Selecting the Variable Density Compensation Model
    You use the variable density compensation model for any solid region with a non-constant solid density. The variable density compensation model applies the corrective energy source term. The corrective energy source is a source term that compensates the changes of the system mass in the energy transport equation due to shrinkage of a solidifying part with temperature-dependent density.
  - Working With the Casting Material Database
    The accuracy of a casting simulation depends on the quality and completeness of the material data that you use. Therefore, a database that contains certified and qualified property data for casting is essential for high quality casting simulations.
    - Accessing the Casting Material Database Editor
      The Casting Material Database Editor allows you to search for material data, view it, and export it to Simcenter STAR-CCM+.
    - Selecting a Casting Material
      You select the casting materials that you want to use from the Casting Material Database Editor. By default, common and private data is displayed, but user-defined data is hidden.
    - Selecting a Material Designation Using the Drop-down Menus
      You can select a material designation from the four drop-down menus that reflect the tree structure.
    - Selecting a Material Designation Using the Icon Lists
      You can select a material designation from the icon lists that are available to the right of the Material Class and Material Group drop-down menus.
    - Selecting a Material Designation Using a String Search
      You can select a material designation using a string search.
    - Selecting a Material Designation Using Its Dataset Number
      You can select a material designation by specifying the dataset number of one of its physical properties:
    - Selecting a Material Designation Using the Search History
      You can select a recently searched material designation from the search history.
    - Viewing Details of the Selected Material Designation
      After you have selected a material designation, the material number and the standard (for example, European, American, British) or a company-defined specification are displayed below the material drop-down menus in the Material Selection panel.
    - Viewing Available Material Properties for a Casting Material
      The Physical Properties panel of the Casting Material Database Editor lets you view the available material properties for the selected material designation.
    - Viewing and Exporting Datasets
      A dataset is a set of data values that represents the variation of a physical property with temperature. In the Casting Material Database, each dataset is assigned a unique number and is associated with a particular casting material designation. A particular physical property of a casting material designation can have two or more datasets that are associated with it.
    - Comparing the Physical Properties of Different Materials
      The Data Comparison panel lets you compare a single physical property for up to five different materials. This feature lets you compare the datasets that are available for particular materials, and select the materials and datasets that are the most appropriate to your simulation.
    - Exporting Casting Material Data to Simcenter STAR-CCM+
    - Working with Private Data
      Within the Casting Material Database, a private material database allows you to work with confidential material data belonging to an individual owner. A private material database can be made available by a person in authority within your company.
    - Working with User-Defined Data
      Within the Casting Material Database, a user-defined material database allows you to run casting simulations with your own material data.
    - Working with the AMat.pro Builder
      You can create and edit private and user-defined material data using the AMat.pro Builder.
  - Importing Casting Materials and Properties in Simcenter STAR-CCM+ From an External File
    You can import casting materials and properties into the Simcenter STAR-CCM+ Material Database. You can then use the materials in a physics continuum, and use the material properties as boundary values.
  - Detecting Shrinkage-Related Defects
    You can use the Macro Porosity model to detect shrinkage-related defects in a cast part. When isolated liquid melt regions occur during the solidification process of a cast part, shrinkage cannot be compensated for by supplying extra melt, and pores form.
  - Defect Prediction Using Criteria Functions
    Criteria functions are post-processing items to help predict casting defects like macro- or micro-porosity and to estimate relevant microstructural quantities such as primary and secondary dendrite arm spacings.
  - Artificial Compressibility
    Typically, for casting simulations, the gas phase is considered to be compressible and the ideal gas law is applied. The melt is a liquid and has a constant density. Therefore, the multiphase mixture is not compressible throughout the entire computational domain. This inhomogeneity results in regions with finite and infinite speeds of sound, which can lead to numerical instabilities and convergence problems.
  - Casting Field Functions
    The following primitive field functions are available to the casting simulation.
  - Casting Bibliography
- 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.

Working with User-Defined Data

Within the Casting Material Database, a user-defined material database allows you to run casting simulations with your own material data.

You can create and edit user-defined material data and store them in the local database file MDB_Scratch.sqlite3 within your home directory.

By default, common and private data is displayed, but user-defined data is hidden.

To display user-defined material data:

In the Casting Material Database Editor, on the Settings menu, activate Show User Defined Data.
In the Material Selection panel, launch the Material Search dialog by running an empty string search.
All material designations, including user-defined ones, are displayed.

To create user-defined material data:

In the Casting Material Database Editor, select an existing material designation whose properties values are close to your user-defined properties.
In the Material Selection panel, click Copy to User Defined Data.
In the Copy material to user-defined data dialog, in the User-defined material designation box, enter the appropriate name.

Alternatively, you can leave the default name composed of the original material designation from which the data have been copied and some postfix notation.
Optional: Enter a comment in the Comment box.
Click OK to confirm the new details.

The user-defined material designation is added to the material subgroup that the original material designation belongs to.

To edit user-defined material data:

In the Casting Material Database Editor, select the user-defined material designation that you want to modify.
In the Material Selection panel, click Edit User Defined Data.
The STAR-Cast Mat Database Builder launches in a separate window.
Edit the relevant material data and datasets.

For information on how to work with the STAR-Cast Mat Database Builder, see Working with the STAR-Cast Mat Database Builder.