Mentor Graphics Makes CFD Meshing Faster
Evan Yares posted on March 04, 2016 |
FloEFD mesh refinement tools help users specify high quality mesh settings faster and more accuratel...
Mesh refinement based on distance from the model's surface. (All images courtesy of Mentor Graphics.)

Mesh refinement based on distance from the model's surface. (All images courtesy of Mentor Graphics.)

Not so long ago, computational fluid dynamics (CFD) was the realm of experts. Complexities in meshing, solver numerics, turbulence modeling, solution convergence, and result interpretation were enough to scare away all but the most intrepid.

One tool that has helped democratize CFD simulations is FloEFD, from Mentor Graphics.

FloEFD is a full-featured general-purpose tool supporting upfront simultaneous CFD analysis. It can be embedded in CAD systems such as Creo, CATIA V5, Siemens NX and SolidWorks. Alternatively, there is a standalone version that tightly integrates with Inventor and Solid Edge.

The recently announced version 15 of FloEFD includes an enhanced transient solver, an engineering design automation (EDA) interface for importing printed circuit board (PCB) data and a connector to Dassault Systèmes' Abaqus finite element analysis (FEA) software for stress analysis.

While these are each major enhancements, for the everyday user the most interesting improvements may be in FloEFD’s meshing features.

FloEFD uses an immersed-boundary mesher to automatically create orthogonal Cartesian meshes from solid models. These meshes can be refined through isotropic splitting, where individual cells are split into eight smaller cells. When creating the mesh it is possible to specify a particular level of refinement based on local requirements. Version 15 includes several tools to make this process easier.

A new equidistant refinement tool allows a user to create zones in the model, within which the cells are of a specified refinement level. These zones are defined by specifying a distance from a surface, part or the entire model. Users can easily set up a mesh for external flow problems by creating zones around the body that can transition the mesh from higher refinement levels to the lower refinement cells.

This equidistant refinement tool can also be applied to internal flow problems (e.g. ducts), where the cells near a wall should be at a higher refinement level.

Small channels and gaps can be solid-filled during the meshing process.

Small channels and gaps can be solid-filled during the meshing process.

FloEFD added an autofill channels tool that can fill gaps in the model with solid cells during the meshing process. Though these gaps may not affect the flow field, they do add to the mesh complexity and may affect the solver's stability or slow its convergence.

FloEFD version 15 allows local regions for cell refinement to be defined graphically by boxes, cylinders or spheres.

New mesh quality tools visualize tolerance, curvature criteria and cell refinement.

While none of these improvements seem major, collectively, they make the process of getting to an optimal mesh faster.

Dr. Geraldo Olivares, senior research scientist at the National Institute for Aviation Research, appreciates the new tools.

“The new improvements in the definition of the mesh settings are an enormous help especially for our external aerodynamics simulation cases,” Dr. Olivares said. “The ability to define layers of refinements, to setting a specific cell size, as well as defining local regions based on basic geometric objects helps us save time we used to spend on defining the correct mesh settings. Other enhancements such as mesh preview and the ability to analyze the mesh quality enable us to specify high quality mesh settings even faster and more accurately.”

What are your favorite addtions to FloEFD? Comment below.

Evan Yares has made his career in the engineering software industry for over 30 years. A recipient of the CAD Society Joe Greco Community Award, he’s been recognized as a champion for users of engineering software. 

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