## Solver: compressibleInterFoam Description

compressibleInterFoam is a solver designed for transient simulations of two compressible, non-isothermal, and immiscible fluids. It handles laminar and turbulent fluid flows. The Volume of Fluid (VoF) approach is used for capturing the interface between the fluids accurately.

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 Multiple Reference Frame (MRF) and porosity modeling and allows easy integration of passive scalar transport equations and source terms.

The application of the solver is very specialized but can be found in the marine industry for the calculation of cavitation bubbles and interactions between them or underwater explosions. In the piping industry, the solver can be used for gas-liquid flows where changes in pressure lead to high-density variation.

## Solver: compressibleInterFoam Features

**Transient****Compressible****Multiphase - Volume of Fluid (VoF)**

- 2 Immiscible Fluids
- Heat Transfer

- Laminar and Turbulent (RANS, LES, DES)
- Equation of State Models
- Pressure-Based Solver
- Rotating Objects:
- Multiple Reference Frames (MRF)

- Passive Scalar
- Porosity Modeling
- Heat Source (temperature source therm)
- Buoyancy
- Source Term (explicit/implicit)
- PIMPLE Algorithm
- MULES Algorithm
- Solution Limiters:
- Velocity Damping

## Solver: compressibleInterFoam Application

**Marine**

- Cavitation Bubble Behavior and Interactions
- Underwater Explosions

**Piping**

- Bubble Dynamics
- Gas-Liquid Flow in Pipelines

**Fuel Systems**

- Sloshing of Fuel in Aerospace Vehicles

## Solver: compressibleInterFoam Multiphase - Free Surface (VoF) Solvers Comparison

Free Surface (VoF) Solvers In this group, we have included solvers implementing **Volume of Fluid (VoF)** approach to handle multiple immiscible and miscible fluids and interactions between them.

**Free Surface (VoF) - Immiscible**

- interFoam 2 immiscible fluids, DyM
- multiphaseInterFoam multiple immiscible fluids, DyM
- interIsoFoam* 2 immiscible fluids, isoAdvector* method, DyM

- overInterDyMFoam extension of interFoam with Overset, DyM
- compressibleInterFoam compressible version of interFoam with heat transfer
- compressibleInterDyMFoam compressible version of interFoam with heat transfer and DyM

**Free Surface (VoF) - Miscible**

- interMixingFoam 3 fluids (2 miscible and 1 immiscible), DyM
- twoLiquidMixingFoam** 2 miscible fluids

- * isoAdvector - an alternative approach for interface capturing, MULES method used in other VoF solvers
- ** Solver designed to handle mixtures consisting of multiple fluids within the same phase, such as two gases or two liquids

- VoF - Volume of Fluid
- DyM - Dynamic Mesh
- Overset - also known as Chimera Grid (Method)

## Solver: compressibleInterFoam 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 | \(U\) [\(\frac{m}{s}\)] |

Temperature | \(T\) [\(K\)] |

Phase Volume Fraction | \(\alpha\) [\(-\)] |

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

Hydrostatic Perturbation Pressure | \(p - \rho gh\) [\(Pa\)] |

**Hydrostatic Perturbation Pressure** This value represents the pressure without the hydrostatic component (minus gravitational potential). Read More: Hydrostatic Pressure Effects

**Derivative Results**

Density | \(\rho\) [\(\frac{kg}{m^{3}}\)] |

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

Mach Number | \(Ma\) [\(-\)] |

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 | \(WSS\) [\(Pa\)] |

Wall Heat Flux | \(\phi_q\) [\(W/m^2\)] |

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