The Turbulent Flow, SSG-LRR (spf) interface () is used for simulating single-phase flows at high Reynolds numbers. The physics interface is suitable for incompressible flows, weakly compressible flows, and compressible flows at low Mach numbers (typically less than 0.3).

The equations solved by the Turbulent Flow, SSG-LRR interface are the Reynolds-averaged Navier–Stokes (RANS) equation for conservation of momentum and the continuity equation for conservation of mass. Turbulence effects are modeled using the Speziale-Sarkar-Gatski/Launder-Reece-Rodi-ω (SSG-LRR) seven-equation transport model. The SSG-LRR model is a so-called low-Reynolds number model, which means that it can resolve the flow all the way down to the wall. The physics interface includes a wall distance equation.

Except where included below, see The Laminar Flow Interface and The Turbulent Flow, k-e Interface for all the other settings.

A different turbulence model of RANS-RSM type can be selected under Turbulence model. Changing the Turbulence model type to RANS-EVM, a turbulence model of RANS-EVM type can be selected under Turbulence model. Laminar or creeping flow may be simulated by changing the Turbulence model type to None.

The Turbulence model property disables the Neglect inertial term (Stokes flow) checkbox, and for 2D components also the Shallow Channel Approximation checkbox.

Low Re option, which enforces resolution all the way down to the wall, is used. This approach demands quite fine mesh near the wall.

For this physics interface the parameters are Cμ, , , , , , ,

For study information, see Stationary with Initialization, Time Dependent with Initialization, and Wall Distance Initialization in the COMSOL Multiphysics Reference Manual.