With all of the buzz of what’s new in SOLIDWORKS 2016, and even SOLIDWORKS Simulation 2016, many engineers that specialize in computational fluid dynamics (CFD) might feel left out. However, the team at SOLIDWORKS has created a series of updates to their CFD tool, SOLIDWORKS Flow Simulation, in the 2016 release.

Meshing Is Key to SOLIDWORKS Flow Simulation 2016

Lotfi Derbal, product portfolio manager for SOLIDWORKS Flow Simulation at Dassault Systèmes, notes that perhaps the most important improvement to the software is its meshing enhancements. “For any simulation, the time spent on meshing is important to the user,” said Derbal. “When you have a large model, it means more CPU time. The compromise is: do you want a quick automatic mesh, or should you spend time to optimize the size of the global mesh?” Typically, an automatic mesh will yield a less desirable computational model than one that is manually optimized by the user. However, Derbal notes that “with current enhancement of the mesh, even with manual operation, you can optimize the mesh very fast … faster than the last version.” Flow Simulation also has the ability to create more uniform meshes for improved convergence and accuracy. This meshing ability can be used for both internal and external flows. Users are able to set local mesh domains within which the mesh is optimized. To define these domains more easily, Flow Simulation 2016 allows users to directly create domains around a specific design detail without adding a geometric feature, which was previously needed. Each domain can be set to have either a particular cell size or cell number for local optimization of the mesh to capture all the detail of the model while still maintaining a uniform mesh around that model.

Another added tool to SOLIDWORKS Flow Simulation is the mesh plot. This tool creates a quick reference the engineer can use to see where the mesh still needs to be refined. The plot shows how many levels of refinement a mesh cell has undergone from the initial global mesh size. The higher the number, the more times a cell’s size has been reduced and thus finer the mesh. This information is useful in understanding if the mesh is well suited for its purpose of capturing both the geometry and the resulting flow field.

Nested Iterations Reduce CFD Computations for Transient Analysis

A significant time saver for engineers will be the ability to use nested iterations when computing a transient analysis. Derbal explained that simulations that traditionally need small time steps can take days or weeks to solve. “If the simulation requires a time step of say 0.1 milliseconds and you want to investigate a range of 5 seconds total, then you are looking at 50,000 time steps," said Derbal. "A compressible gas flow in a vessel, for example, can take days to calculate.” With the nested iterations, however, much larger time steps are permissible, reducing your computational time considerably. Derbal noted that the new computation will not be able to capture tiny transient details in the results, so the accuracy may be reduced by a small percentage. However, if that accuracy level is good enough for your simulation, then the time savings is well worth it.

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