Using COMSOL Multiphyiscs, Mahindra Two Wheelers was able to optimize the purr of this beauty. Motorcycles are an inherent multiphysics problem. (Image courtesy of Mahindra.)
Every engineer that hits the road understands the elements of structural analysis, fluid dynamics, heat transfer, noise, vibration and harshness (NVH) that go into engine designs.
It’s clear we live in a world of multiphysics. This is why software like COMSOL Multiphysics is so important to solving design problems.
COMSOL Simulates the Multiphysics Intrinsic to the World
Using COMSOL Multiphysics, Mahindra’s engineers created simulations and apps to better understand how structures in the engine could control the purr. (Image courtesy of Mahindra.)
Unfortunately, even today there are computer-aided engineering (CAE) software options that are unable to expand into the realm of coupled physics. Marra explained that those that do have multiphysics tend to couple the equations after discretization, forcing the need of user defined subroutines which can get complicated and tedious. Much of this is due to the creation of simulation software at a time when computational power was miniscule and simplifications were mandatory.
CAE engineers all know that 3D simulation software is based on numerical methods. From finite difference and finite volumes to finite elements, these tools are used to approximate the differential equations that are generally impossible to solve analytically. To simplify this process, most CAE software predefine these numerical models.
With COMSOL Multiphysics, however, “a full mathematical model is generated on the fly, based on user input, before the discretization is created when the user clicks the solve button,” explained Valerio Marra, Marketing Director at COMSOL.
“It is difficult to add phenomena and descriptions of variables and multiphysics couplings to a numerical model if they are not considered in the differential equations from the beginning,” added Marra. “COMSOL gives users access to readily available physics and the ability to create their own expressions and multiphysics couplings by using the names of variables and coordinates and by directly typing the mathematical expressions in the user interface.”
Now, of course engineers can still use COMSOL to model problems that can be accurately described using a single physics—say, just the flow of the exhaust exiting the engine. The advantage here is that the engineer can then add more physics—such as the purr the exhaust makes when it escapes—if they choose to expand it.
Marra added that users can input arbitrary mathematical expressions that could, for instance, describe material properties, loads, sources, sinks and multiphysics couplings. He explained that this is an approach that leads to accurate results.
Additionally, Marra explained that where COMSOL’s form of multiphysics is most useful is when a problem can’t be simplified. Take Ashim Datta’s research on the engineering and science of puffing rice. This research represents a fully coupled problem that incorporates evaporation, heat transfer, mass transfer, momentum transport, plastic deformation and pressure buildup.
“Sometimes the physics can be so intertwined that any attempt at simplifying your mathematical model precludes the possibility of getting any meaningful information from the simulation. In cases such as these, coupling more than one physics is necessary from the beginning. COMSOL has built-in flexibility so that any user can work with the modeling approach that makes the most sense to them,” Marra said.
COMSOL’s App Builder and Server Democratize Simulation
Engineers can benefit from a new tutorial which simulates vibration and noise in a five-speed synchromesh gearbox housed within a manual transmission car. (Image courtesy of COMSOL.)
If there is one thing Svante Littmarck, president and CEO of COMSOL, is most excited about, it is COMSOL’s continual focus on simulation apps. In the recent 5.3 release, users will be able to create apps for multiphysics models.
“It’s exciting to see how customers are benefiting from building and deploying simulation apps,” Littmarck said. “Case studies across industries are demonstrating how simulation specialists are leveraging simulation apps to expand the use of multiphysics simulation.”
One example of an interesting simulation app comes from Mahindra Two Wheelers. The company’s app simulates the noise, vibration and harshness (NVH) from a motorcycle’s engine, intake and exhaust.
“We created a simulation app using the Application Builder to compare analysis output files and plot the sound pressure level data, which was a great time saver,” said Ulhas Mohite, manager at Mahindra. The firm’s app could assess the acoustics of the motorcycle and compare and study the results. Marra explained that apps like this will help organizations like Mahindra simulate faster, reducing the reliance on physical prototypes and getting products to market faster.
He has a point. Cornell Dubilier, suppliers of high end capacitors, housed its simulation app on the COMSOL Server so that engineers at the manufacturing site could help design the product. This gave the design engineers more information to work with when optimizing the design. Additionally, since the simulation analysts offloaded much of the CAE work on this project, they could work on more strategic projects.
“Using COMSOL Multiphysics and its Application Builder, I can create models and build apps based on them. This allows other departments to test different configurations for their particular requirements and pick the best design,” Sam Parler, research director at Cornell Dubilier, remarked.
In the 5.3 release, apps can now be more interactive as the App Builder gives the ability to define custom actions for when a user clicks on a plot or graphical object.
The app interface can be accessed with a browser client or Windows client on the COMSOL Server.
Speaking about the COMSOL Server, some of its updates include the logging of user activity and centralization of administrative settings to run apps on clusters.
What Else is New in COMSOL 5.3?
Boundary element method gives engineers the ability to simulate the electrochemical potential of this oil rig within sea water. (Image courtesy of COMSOL.)
“Our users will find great value in new solvers, the new physics interfaces and the many enhancements throughout COMSOL software, from model creation to deployment of apps,” Littmarck explained.
A valuable addition to COMSOL 5.3 is the ability to use boundary element method (BEM) for electrostatic and corrosion simulations.
“This means that users can easily combine boundary element and finite element methods for greater flexibility in their multiphysics simulations,” explained Littmarck.
BEM is able to simulate designs that contain infinite domains and voids. It can also model designs that contain parts with differing dimensionality such as wires, beams, surfaces, and solids.
Some simulation applications of BEM include electrical cathodic protection, cables and capacitive sensors.
AMG solver used to model the fluid-structure interaction of this solar panel. (image courtesy of COMSOL.)
The AMG solver gives engineers the ability to solve large fluid flow simulations with one mesh level. CFD users will also welcome the automatic wall treatment for turbulent flows blending wall functions with high-fidelity low Reynolds formulations.
The BEM and AMG solvers aren’t the only way COMSOL 5.3 is supporting large complex models. For instance, the Model Builder has a new way to automatically remove geometry features using virtual geometry operations.
“We continue to see improved performance for large models across the board. This is not only about solution time but also how the software handles large models in the user interface, including geometry and mesh,” Bjorn Sjodin, VP of Product Management at COMSOL, noted.
Additionally, the Model Builder now includes model methods which help to automate tedious and complicated operations, which COMSOL promises will improve productivity.
“You can now simply record a set of operations, like a macro, and use the resulting method while setting up or solving a model. This is an important usability feature with many possible applications. For example, you can create a reusable model method that generates a complicated array of geometric objects to expand on the standard functionality of the Model Builder,” Sjodin explained.
Finally, the Model Builder also makes it easier to combine multiple mesh types within models by automatically creating transitions between the meshes using pyramidal elements. This function is compatible with:
- Swept elements
- Hexahedral elements
- Prismatic elements
- Tetrahedral elements
For a detailed look at what is new in COMSOL 5.3 follow this link.
COMSOL has sponsored this post. They have no editorial input to this post. All opinions are mine. — Shawn Wasserman