## Solver: overPimpleDyMFoam Description

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

Based on pimpleFoam, 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 PIMPLE (merged PISO-SIMPLE) algorithm for pressure-momentum coupling. This algorithm leverages the strengths of both PISO and SIMPLE methods for pressure-velocity coupling, ensuring robustness in handling transient flows with large time steps. This approach is supplemented by under-relaxation techniques to secure convergence stability. It supports both Multiple Reference Frames (MRF) and porosity modeling and allows easy integration of passive scalar transport equations and source terms. The solver handles dynamic meshes.

With the overset mesh capabilities, the solver offers a flexible and powerful tool for simulating a broad range of fluid dynamics problems across various industries. In the automotive industry, the flow around moving car components can be analyzed, for example, the flow around the rotating wheels or moving suspension system. In the aerospace industry, the complex movements of aircraft, including significant wing movement, can be considered. Internal flows can be calculated considering the rotation of the mesh as happens in stirring tanks or mixers.

## Solver: overPimpleDyMFoam Features

**Transient****Incompressible****Single-Phase**

- Low-Speed Flows
- PIMPLE 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: overPimpleDyMFoam Application

**Automotive Industry**

- Flow Around the Rotating Wheel
- Flow Around Moving Suspension System

**Aerospace Industry**

- Aircraft Aerodynamics with Significant Motion
- Flow Around Flight Controls with Significant Motion

**Internal Flows**

- Flow in Stirring Tanks
- Flow in Mixers

**Energy Industry**

- Wind Turbines with Rotating Blades

## Solver: overPimpleDyMFoam 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: overPimpleDyMFoam 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 | \(\omega\) [\(\frac{1}{s}\)] |

Courant Number | \(Co\) [\(-\)] |

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 | \(Avg\) \(Min\) \(Max\) |