The High Mach Number Flow, SSG-LRR (hmnf) interface (), found under the High Mach Number Flow > Turbulent Flow branch () when adding a physics interface, is used to model gas flows at high Reynolds number where the velocity magnitude is comparable to the speed of sound, that is, turbulent flows in the transonic and supersonic range.

The physics interface solves for conservation of energy, mass, and momentum. Turbulence effects are modeled using the Speziale–Sarkar–Gatski/Launder–Reece–Rodi-ω (SSG-LRR) model, which solves six transport equations for the turbulence Reynolds stress tensor and a transport equation for the specific dissipation rate. Flow and heat transfer close to walls are modeled using Low Re wall treatment, which enforces resolution all the way down to the wall and, hence, demands quite fine mesh near the wall. The physics interface also supports heat transfer in solids as well as surface-to-surface radiation.

This is a predefined multiphysics interface combining SSG-LRR turbulence model for compressible flow with a heat transfer model. As shown in Table 5-1, the turbulent versions of the physics interfaces differ by where they are selected when adding a physics interface and the default turbulence model selected — SSG-LRR for this physics interface.

When this physics interface is added, the following default nodes are also added in the Model Builder — Fluid, Wall, Thermal Insulation, and Initial Values. Then, from the Physics toolbar, add other nodes that implement, for example, boundary conditions, volume forces, and heat sources. You can also right-click the node to select physics features from the context menu.

The default Turbulence model type is RANS-RSM, the default Turbulence model is SSG-LRR. The Heat transport turbulence model can be set to Turbulent Prandtl number (the default) or Anisotropic turbulent thermal conductivity.

Alternatives for the Turbulent Prandtl number model are Kays–Crawford (default), Extended Kays–Crawford, and User-defined turbulent Prandtl number. For Extended Kays–Crawford, enter a Reynolds number at infinity Re∞. For User-defined turbulent Prandtl number, enter a Turbulent Prandtl number PrT.

When the Anisotropic turbulent thermal conductivity option is used, the turbulent thermal conductivity is defined by the selected Anisotropic turbulent thermal conductivity model option: Daly–Harlow (GGDH) (default), Abe–Suga (High order GGDH), or User-defined turbulent thermal conductivity. For Daly–Harlow (GGDH), enter the Daly–Harlow model coefficient CG. For Abe–Suga (High order GGDH), enter the Abe–Suga model coefficient CH. For User-defined turbulent thermal conductivity, select Isotropic, Diagonal, Symmetric, or Full based on the characteristics of the turbulent thermal conductivity, and enter a value or expression. For Isotropic enter a scalar which will be used to define a diagonal tensor. For the other options, enter values or expressions into the editable fields of the tensor.

The values or expressions required are entered in the Model Inputs section of the Fluid feature node. For the description of theory of turbulent heat transport see Turbulent Conductivity.

Edit the model parameters of the SSG-LRR model as needed. Turbulence model parameters are optimized to fit as many flow types as possible, but for some special cases, better performance can be obtained by tuning the model parameters. For a description of the turbulence model and the included model parameters see Theory for the Turbulent Flow Interfaces.

The dependent variables (field variables) are the Velocity field u (SI unit: m/s), the Pressure p (SI unit: Pa), and the Temperature T (SI unit: K). For turbulence modeling and heat radiation, the six components of Kinematic Reynolds stress uu, vv, ww, uv, uw, vw (SI unit: m2/s2), and the Specific dissipation rate om (SI unit: 1/s), and the Reciprocal wall distance G (SI unit: 1/m) variables are also available.