## Solver: overSimpleFoam Description

overSimpleFoam is a pressure-based solver designed for steady-state simulations of incompressible flow. It handles laminar and turbulent, single-phase flows under isothermal conditions, accommodating both Newtonian and non-Newtonian fluids.

Based on simpleFoam, the solver enhances its predecessor’s capabilities by incorporating overset (Chimera) meshes. This advancement makes the solver particularly suitable for scenarios involving significant object motion, where traditional dynamic meshes prove inadequate.

The overset framework offers a universal approach to implementing overset meshes for both stationary and dynamic scenarios. It utilizes mappings from cell to cell across various, separate mesh regions to create a unified domain. This approach facilitates intricate mesh movements and interactions without the drawbacks typical of mesh deformation.

The solver uses the SIMPLE (Semi-Implicit Method for Pressure-Linked Equations) algorithm for pressure-momentum coupling, augmented by under-relaxation techniques to enhance convergence. It supports both Multiple Reference Frame (MRF) and porosity modeling and allows easy integration of passive scalar transport equations and source terms.

The solver enables detailed analysis of complex flow problems in aerospace, automotive, marine engineering, and beyond. Its integration with overset mesh technology allows for efficient handling of dynamic geometries and moving boundaries, making it an essential tool for optimizing designs and improving performance across various industries.

## Solver: overSimpleFoam Features

**Steady-State****Incompressible****Single-Phase**

- Low-Speed Flows
- SIMPLE Algorithm
- Subsonic Flow (Ma < 0.3)
- Overset (Chimera) Meshes

- Laminar and Turbulent (RANS, LES, DES)
- Newtonian and Non-Newtonian Fluid
- Pressure-Based Solver
- Rotating Objects:
- Multiple Reference Frames (MRF)
- Rotating Mesh Motion

- Passive Scalar
- Porosity Modeling
- Source Term (explicit/implicit)
- Solution Limiters:
- Velocity Damping

## Solver: overSimpleFoam Application

**Aerospace Industry**

- Flows around Flaps
- Flows around Landing Gears

**Automotive Industry**

- Flow around Spoilers

## Solver: overSimpleFoam Incompressible Solvers Comparison

Incompressible Solvers In this group, we have included single-phase, pressure-based solvers for **low-speed flows** with negligible variations in density, applicable for **external** and **internal aerodynamics** (**Ma < 0.3**) and **hydrodynamics**. These solvers use incompressibility features for stability and robustness.

**Incompressible, Stedy-State - Main Solvers**

- simpleFoam steady-state, SIMPLE algorithm
- overSimpleFoam extension of simpleFoam with Overset
- SRFSimpleFoam variant of simpleFoam resolved in SRF

**Incompressible, Transient - Main Solvers**

- pimpleFoam transient, PIMPLE algorithm, DyM
- overPimpleDyMFoam extension of pimpleFoam with Overset, DyM
- SRFPimpleFoam variant of pimpleFoam resolved in SRF

**Incompressible, Transient - Simplified Solvers***

- * Dedicated solvers for simplified scenarios, improve stability and computational efficiency
- ** The PISO algorithm is used for cases with a small Courant number Co < 1

- DyM - Dynamic Mesh
- MRF - Multiple Reference Frame
- SRF - Single Reference Frame
- Overset - also known as Chimera Grid (Method)
- SIMPLE - Semi-Implicit Method for Pressure-Linked Equations
- PIMPLE - merged PISO and SIMPLE
- PISO - Pressure-Implicit Split-Operator

## Solver: overSimpleFoam Results Fields

This solver provides the following results fields:

**Primary Results Fields**- quantities produced by the solver as default outputs**Derivative Results**- quantities that can be computed based on primary results and supplementary models. They are not initially produced by the solver as default outputs.

**Primary Results Fields**

Velocity | \(U\) [\(\frac{m}{s}\)] |

Pressure | \(p\) [\(Pa\)] |

**Derivative Results**

Pressure | \(P\) [\(Pa\)] |

Vorticity | \(\omega\) [\(\frac{1}{s}\)] |

Peclet Number | \(Pe\) [\(-\)] |

Stream Function | \(\psi\) [\(\frac{m^2}{s}\)] |

Q Criterion | \(Q\) [\(-\)] |

Wall Functions (for RANS/LES turbulence) | \(y^+\) [\(-\)] |

Wall Shear Stress | \(WSS\) [\(Pa\)] |

Turbulent Fields (for RANS/LES turbulence) | \(k\) \(\epsilon\) \(\omega\) \(R\) \(L\) \(I\) \(\nu_t\) \(\alpha_t\) |

Volumetric Stream | \(\phi\) [\(\frac{m^{3}}{s}\)] |

Passive Scalar | \(scalar_i\) [\(-\)] |

Forces and Torque acting on the Boundary | \(F\) [\(N\)] \(M\) [\(-\)] |

Force Coefficients | \(C_l\) [\(-\)] \(C_d\) [\(-\)] \(C_m\) [\(-\)] |

Average, Minimum or Maximum in Volume from any Result Field | \(Avg\) \(Min\) \(Max\) |