COMSOL Multiphysics^® 6.4 リリースハイライト

For users of the Mixer Module, COMSOL Multiphysics^® version 6.4 introduces an efficient alternative for modeling rotating domains, improved initial conditions for advanced turbulence models, and more. Read more about these updates below.

Rotating Frame Feature as an Alternative to Rotating Domains

The new Rotating Frame feature expresses fluid flow equations relative to a stationary or time-dependent rotating frame, providing an inexpensive alternative to rotating domains without having to add equations. It also offers options for using a reduced pressure formulation or including the hydrostatic pressure approximation for the centrifugal force.

Streamlines and pressure in a centrifugal separator rotating at 9550 rpm, modeled using the new Rotating Frame feature.

Algebraic Turbulence Models for High Mach Number Flows in Rotating Machinery

The L-VEL and Algebraic yPlus turbulence models are now available for high Mach number flows in rotating machinery. These algebraic models are primarily used to generate optimal initial conditions for more advanced turbulence models, improving convergence and providing better starting points for time-dependent simulations, for example, when simulating turbomachinery.

The Algebraic yPlus turbulence model shown in the Settings window with the option to change to the L-VEL turbulence model. The Graphics window shows flow streamlines in a plane around two rotating blades, with the color representing the Mach number.

Scale-Adaptive Unsteady Turbulent Flow Simulations

The Turbulent Flow, SST interface now supports scale-adaptive simulation (SAS) by incorporating the von Kármán length scale into the turbulence model. This approach resolves a broader range of turbulent scales and provides highly detailed flow fields. SAS can be applied in multiphysics contexts such as fluid–structure interaction, reacting flow, nonisothermal flow, and flow-induced noise, delivering more accurate and insightful results.

Unsteady flow over a tandem cylinder configuration visualized using the Q-criterion, which represents isosurfaces of the difference between the squared vorticity magnitude and the squared strain-rate magnitude.

Elliptic Blending R-ε Turbulence Model with Improved Near-Wall Treatment

By blending expressions for the pressure–strain correlation and the turbulence viscous dissipation rate in the near-wall region with those in the bulk, the new Turbulent Flow, Elliptic Blending R-ε turbulence model provides accurate results for the Reynolds stresses close to walls without compromising the behavior elsewhere.

The settings of the Turbulent Flow, Elliptic Blending R–ε interface, showing the four available Reynolds-stress diffusion models.