Understanding Physics Modelling in STAR-CCM
- The purpose of stopping criteria is to specify how long the solution runs for and under what conditions it stops iterating and/or marching in time.
- Each specified stopping criterion is evaluated at the completion of every simulation step and a logical rule is used to determine if the interaction of all of the criteria stops the solver.
Physics Models used for External Aerodynamics Simulation
1) Modeling 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. There are four models as follows:
- The Axisymmetric Model
- The Shell Three-Dimensional Model
- The Two-Dimensional Model
- The Three-Dimensional Model
2) Modeling 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. There are 5 models as follows:
- Steady
- Explicit Unsteady
- Implicit Unsteady
- PISO Unsteady
- Harmonic Balance
3) Material Models: A material model is responsible for managing the material, that is, substance or substances, being simulated in the continuum. The simulated material is responsible for managing the various thermodynamic and transport properties relevant to that material and to the physical processes being modeled in the continuum.
There are three general types of material models available in Simcenter STAR-CCM+:
- single-component (Only one pure substance in any phase)
- multi-component (Mixture of Miscible pure substances in same phase)
- multiphase mixture (Two or more Immiscible phases)
4) Flow Models: The Flow types such as Inviscid flow, Viscous flow, Laminar flow, Transitional flow and Turbulent flow can be modeled.
As Fluids exhibit different behaviours depending on their properties, Simcenter STAR-CCM+ provides several flow models
- Segregated Flow and Energy
- Coupled flow and energy
- Viscous flow and energy
5) Modelling the Equation of state: The Equation of State model is used to compute the density and the density derivatives with respect to temperature and pressure. Whether the fluid is of constant density, Ideal gas or real gas can be selected.
6) Turbulence Models: To Model turbulence in fluid flows, the following turbulence models from RANS category can be selected:
- K-epsilon Turbulence
- K-omega Turbulence
- Reynolds stress Turbulence
- Spalart Allmaras Turbulence
A cube of side 1 cm is modelled, meshed and the physics models are set up
The following meshers are used:
A section of the mesh is shown below
The following physics models are selected:
The following boundary conditions are used: