## Solver: SRFSimpleFoam Description

srfSimpleFoam is a pressure-based solver designed for the steady-state simulations of incompressible flows. It is capable of handling both laminar and turbulent, single-phase flows under isothermal conditions. This solver accommodates a range of fluid types, including Newtonian and non-Newtonian fluids, within a Single Rotating Frame (**SRF**). It is an adaptation of the simpleFoam solver, distinguished primarily by its ability to model fluid flow within a rotating reference frame.

**SRF** is a technique employed for simulating rotating machinery, such as fans, compressors, or turbines, within a fixed simulation domain. This method simplifies the simulation process by eliminating the need to physically rotate the mesh, thus conserving computational resources and time. In this approach, rotational effects are incorporated through boundary conditions and source terms in the governing equations, introducing two additional forces: the Coriolis force and the centrifugal force.

The solver utilizes the **SIMPLE** (Semi-Implicit Method for Pressure-Linked Equations) algorithm for efficient pressure-momentum coupling, further enhanced by under-relaxation techniques to improve convergence rates. It supports the use of porosity modeling, integrates passive scalar transport equations, and source terms.

`srfSimpleFoam`

proves particularly beneficial for simulations in which the rotation is constant, focusing on the cumulative effect of rotation over time. Its application is prevalent in the design and analysis of HVAC systems, turbo-machinery, and other rotating equipment, making it a valuable tool in these fields.

## Solver: SRFSimpleFoam Features

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

- Low-Speed Flows
- SIMPLE Algorithm
- Subsonic Flow (Ma < 0.3)
- Single Rotating Frame (SRF)

- Laminar and Turbulent (RANS, LES, DES)
- Newtonian and Non-Newtonian Fluid
- Pressure-Based Solver
- Rotating Objects:
- Passive Scalar
- Porosity Modeling
- Source Term (explicit/implicit)
- Solution Limiters:
- Velocity Damping

## Solver: SRFSimpleFoam Application

**HVAC Industry**

- Fans and Blowers

**Turbomachinery**

- Blade Shape Optimization
- Centrifugal Pumps
- Fans

**Wind Turbines**

- Airflow around Rotating Blades

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

Kinematic Pressure \(p/\rho\) | \(p\) [\(\frac{m^{2}}{s^{2}}\)] |

**Kinematic Pressure** It is a pressure normalized by density. To obtain pressure in Pascals [Pa], multiply kinematic pressure by the fluid’s reference density. Read More: Kinematic Fluid Properties

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