## Solver: cavitatingFoam Description

cavitatingFoam is a pressure-based solver designed for transient flow simulations with cavitation, utilizing the Homogeneous Equilibrium Model (HEM). The HEM model is used to determine the compressibility of the liquid/vapor ‘mixture’, whose density varies from liquid to vapor density according to the selected barotropic equation of state.

The solver allows for the selection of RANS (Reynolds-Averaged Navier-Stokes) and LES (Large Eddy Simulation) turbulence models, accommodating both Newtonian and non-Newtonian fluids. The mixture compressibility \(\psi\) (defined as a reciprocal of a square of the speed of sound) defines the relation between density and pressure within the system. The \(\psi\) function is determined based on one of the available barotropic compressibility models: linear, Chung and Wallis. By offering varied approaches to represent the speed of sound within the liquid/vapor mixture, these models significantly influence the accuracy of cavitation simulation.

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.

The solver’s capability to accurately model cavitation dynamics offers substantial benefits across several industries. For instance, in the marine sector, it enables precise predictions of cavitation around propellers. In the piping industry, understanding cavitation within valves is crucial for enhancing their durability. Similarly, the solver aids in assessing cavitation effects on hydrofoils, which is vital for their endurance and performance.

## Solver: cavitatingFoam Features

**Transient****Incompressible****Multiphase - Homogeneous Equilibrium Model (HEM)**

- 2 Immiscible Fluids (Liquid & Vapor)
- Cavitation
- Homogeneous Equilibrium Model (HEM)

- Laminar and Turbulent (RANS, LES, DES)
- Newtonian and Non-Newtonian Fluid
- Pressure-Based Solver
- Passive Scalar
- PIMPLE Algorithm
- Solution Limiters:
- Velocity Damping

## Solver: cavitatingFoam Application

**Rotating Machinery**

- Pumps (in the fixed position)
- Turbines (in the fixed position)

**Marine Industry**

- Propellers (in the fixed position)
- Hydrofoils

**Piping Industry**

- Piping Systems
- Valves

**Automotive Industry**

- Diesel Injector Nozzle

## Solver: cavitatingFoam Multiphase - Phase Change Solvers Comparison

Phase Change Solvers In this group, we have included solvers implementing **Phase Change** models to handle cavitation, and surface evaporation/condensation (liquid and its vapor phases).

**Phase Change - Cavitation**

- cavitatingFoam 2 immiscible fluids, dedicated to cavitation, Homogeneous Equilibrium Model (HEM)
- interPhaseChangeFoam 2 immiscible fluids, dedicated to cavitation, VoF, Phase Change Models: Schnerr-Sauer, Merkle, Kunz

- cavitatingDyMFoam extension of cavitatingFoam with DyM
- interPhaseChangeDyMFoam extension of interPhaseChangeFoam with DyM
- overInterPhaseChangeDyMFoam extension of interPhaseChangeFoam with Overset, DyM

**Phase Change - Condensation / Evaporation**

- interCondensatingEvaporatingFoam 2 immiscible fluids, phase changes (evaporation and condensation) between a fluid and its vapor phase

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

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

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

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

**Derivative Results**

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

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

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