Simcenter Boosts Its CFD and Autonomous Simulation Tools

Simcenter STAR-CCM+ sees hypersonic, multiphase and cyclic motion improvements. Simcenter Prescan C++ updates Unreal Physics-Based Camera.

Simcenter STAR-CCM+ and Simcenter Prescan C++ 2021.2 Show Off Upgrades Across Multiple Disciplines

When Siemens recently announced the 2021.2 update of its Simcenter STAR-CCM+ computational flow dynamics (CFD) software, it hit the highlights across multiple disciplines and industries. Instead of building a long list of incremental improvements, the What’s New announcement hit on some key applications where the improvements are already in place.

Vehicle Thermal Management CFD. (Image courtesy of Siemens.)

Vehicle Thermal Management CFD. (Image courtesy of Siemens.)

Periodic cyclic motion, thermal management, multiphase simulations and hypersonic studies all received new features. Other improvements include fluid-structure interactions, faster meshing power and a change to the software’s crowdsourcing community.

Simcenter Prescan C++ 2021.2 also boasts updates and feature additions to its physics-based camera simulations and two-dimensional dynamics. The advanced driver-assistance systems (ADAS) data validation tool continues to work toward the goal of shorter feedback loops and more accurate data for vehicle engineers.

Making Wise Choices During a CFD Computation Plan

In his article, 4 ways to CFD speed-up: don’t calculate hard-calculate smart!, Carlo Locci says that CFD speed-up is one of a simulation engineer’s main duties. As computing power gets faster and more powerful, it isn’t enough to just contentedly take advantage of the speed. We should also try and make better decisions about what is being analyzed. Locci explains some of the methods that Simcenter STAR-CCM+ uses to get the most of its advanced computing power.

WATCH: Feature Can Use the Same Mesh Data Every 30 Degrees. (Image courtesy of Siemens.)

WATCH: Remeshing Feature Can Use the Same Mesh Data Every 30 Degrees. (Image courtesy of Siemens.)

The article touches on clustering methods used to calculate several variables at once and continually reuse those numbers in a study. Adaptive Mesh Refinement lets the user focus attention on the areas of interest and lessen the calculations required on the rest of a model. Simulations Operations helps to rectify studies where both short- and long-time scales are in play. Using the short-time scale would take far too long to calculate everything, but the long-time scale would lose accuracy. In one example from another article, switching back and forth between time scales made the computation 40 times faster without losing accuracy.

The star idea from Locci’s articles is the refined meshing feature available in the Simcenter STAR-CCM+ 2021.2 release. Looking at two rotating gears in a pump assembly, the model needs to be remeshed every 2.5 degrees to give accurate results. In the specific example used the gears have twelve teeth so the study repeats itself every 30 degrees. In this specific example, building 12 sets of the mesh for the study to pull from makes the entire calculation almost twice as fast.

Hybrid Multiphase Analysis Helps to Do the Dishes

David Mann writes about some of his multiphase inspiration in an article about hybrid multiphase simulations. Watching his kids pour water back and forth between cups and the subsequent act of cleaning up the puddles after the kids started him thinking. Volume of fluid (VOF) analysis transitioning to straight film analysis can cause problems where the engineer needs to decide which set of references to use for a calculation.

Using Siemens’ Adaptive Mesh Refinement lets the user place a fine mesh where detailed results are needed and a coarser mesh in less intense areas. The theoretical example shown in the article shows a fluid sitting in containers, then dropping into a jet and finally sitting as a film on top of a surface. The adaptive mesh tightens up around the jet and in the transition areas but is much wider around the container portions.

The industrial example in the article shows how Adaptive Mesh Refinement can be applied to a dishwasher. The dishwasher uses jets of water in a radial motion, and the water spreads into drops and also splashes against several surfaces. Mann says that traditional methods of calculation are “computationally expensive as we must use large areas of dense mesh where it is only needed temporarily.” However, using adaptive mesh shows that some mesh is coarse, and some is fine at any given moment, and those differences change over time. The adaptive mesh used in this example took the total computing time of the 40 CPUs running the analysis from 2.212 days to 0.805 days.

CFD and the Apollo Space Program

The 2021.2 release of Simcenter STAR-CCM+ changed the way that surface temperature distribution is built in hypersonic flow. A uniform heat flow around an object can help give a model symmetric surface heating, and the most immediate real-world beneficiary to these changes is the space program. The Carbuncle Effect that creates anomalies in high-speed flow analysis can be lessened by using this uniform flow distribution.

Simcenter Studies Hypersonic Flow During Apollo Reentry. (Image courtesy of Siemens.)

Simcenter Studies Hypersonic Flow During Apollo Reentry. (Image courtesy of Siemens.)

Testing for the 2021.2 release included the Apollo 11 Command Module and Space Shuttle Columbia for analysis cases. Instead of relying on expensive unmanned flights and wind tunnels for testing, Siemens hopes that its advanced shock and aerothermal heating tests can provide insight into the space program. 

Simcenter Prescan C++ Adds Unreal Physics-Based Camera

Engineers developing automated vehicles can now use the Unreal Physics-Based Camera (PBC) to create more realistic images. Ray tracing is added to the reflections commands, along with flare and convolution bloom effects. Users now have the option to dictate the camera’s exposure and gain control, and these options can also be applied to the fisheye PBC.

Unreal Physics-Based Camera Simulation from Prescan C++. (Image courtesy of Siemens.)

Unreal Physics-Based Camera Simulation from Simcenter Prescan C++. (Image courtesy of Siemens.)

Simcenter Amesim is helping give Simcenter Prescan C++ new features with a new two-dimensional dynamics model offering 15 degrees of freedom. The models are built around small cars, medium cars, SUVs and non-articulated actors. This addition should let users quickly add additional models to a simulation. Additionally, the FAW Jiefang J6M and John Deere 8400r are added as new assets for users to plug into a study.

OpenDRIVE v1.6 files can now be imported into Simcenter Prescan C++, and 3D roads can be built using variable road elevation. Sidewalks can have different heights if created through the DMAPI, and dashed line road markers can now be built with a rhomboid shape. OpenSCENARIO is updated with the capability to create dynamic scenarios and a Relative Speed Condition to define an object’s speed with respect to the speed of other objects. Time Headway Condition and Traveled Distance Conditions are two other new pieces added for users to trigger events.

So Many Changes, and More Coming All the Time

The more you look through the various articles and posts about the Simcenter STAR-CCM+ and Simcenter Prescan C++ updates, the more you realize the scope of these changes. Some of the work based around these improvements were in development in 2018, and some others were first mentioned in early 2021. Multiple updates are released every year, and it’s staggering to think of the infrastructure in place to build new features, evaluate and prioritize the changes, and finally implement the adjustments on the fly all while servicing current customers and the software release that is already in place.

Siemens has always been in tune with its users and the features that users would like added to their products, and the company has now pushed a little further into the crowdsourcing realm. Ideastorm was the previous platform for people to submit new product ideas while voting and commenting on the ideas of other users. That system is now replaced by the Simcenter Community for Simcenter STAR-CCM+ where customers and product management teams can discuss the software and their ideal changes or upgrades. More than 4,500 ideas have been submitted since the program began in 2013, and Siemens says that over 900 changes from the community were implemented.