## Solver: cavitatingDyMFoam Description

cavitatingDyMFoam is a pressure-based solver optimized for simulating transient flows experiencing cavitation, leveraging the Homogeneous Equilibrium Model (HEM) for its calculations. This model is instrumental in assessing the compressibility of the liquid/vapor mixture, with its density transitioning from that of a liquid to that of a vapor, guided by the chosen barotropic equation of state. It is an extension of the cavitatingFoam solver additionally supporting the functionality of dynamic mesh motion.

The solver supports the use of both RANS (Reynolds-averaged Navier-Stokes) and LES (Large Eddy Simulation) models for turbulence, capable of handling fluids that are either Newtonian or non-Newtonian. The compressibility of the mixture \(\psi\) (the inverse of the sound speed squared) establishes how density and pressure affect each other in the mixture. \(\psi\) is calculated with the help of barotropic compressibility model - linear, Chnug, or Wallis.

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 dynamic mesh capabilities of the solver extend its applications. In the marine industry, the cavitation can be calculated using the rotating propellers. The plug motion can be simulated in the valve to check the movement influence on the cavitation conditions. Cavitation in rotating pumps can be investigated, which is important in the rotating machinery field.

## Solver: cavitatingDyMFoam Features

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

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

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

- Passive Scalar
- PIMPLE Algorithm
- Solution Limiters:
- Velocity Damping

## Solver: cavitatingDyMFoam Application

**Rotating Machinery**

- Rotating Pumps
- Rotating Turbines

**Marine Industry**

- Rotating Propellers

**Piping Industry**

- Valves with the Plug Motion

## Solver: cavitatingDyMFoam 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: cavitatingDyMFoam 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 | \(Avg\) \(Min\) \(Max\) |