A Supercomputer Equal to 60,000 PCs

INNOVATION

While an ordinary PC would need more than 600 years to compute all of the impact simulations performed in the development of the ŠKODA KODIAQ, the ŠKODA Data Centre uses a supercomputer that could do the same job in a matter of months. How exactly?

17. 4. 2018

Now, you might be asking yourself what exactly a supercomputer is. Technically speaking, a supercomputer integrates a large number of highly powerful computers into a single unit whose individual parts communicate with each other via high-speed networks. To give you a sense of scale, the power of its hardware is equivalent to that of approximately 60,000 ordinary PCs. The supercomputer in ŠKODA Data Centre is the most powerful non-governmental computing centre in Central and Eastern Europe. Following its scheduled expansion this year, the supercomputer’s energy consumption is equal to the annual power generated by a small hydroelectric plant. The system is designed to perform multiple complex calculations simultaneously.

“For the supercomputer to perform such calculations, we need to feed it with data and maintain enough space to save this data as it comes in,” explains Michal Krupička, IT Business Analyst for Computing Systems. “Its operation depends on many other infrastructure servers. Some of them receive input requests from users and configure their own computing tasks (determining where and how the computing is to take place), some supervise the task-planning process over time while striving to meet all user requirements fairly, and others constantly probe the network for glitches (perhaps where a memory has stopped working or a network cable gets disconnected). Each part of the supercomputer continuously communicates with a database, receiving information as to what should be run and how. In return, the supercomputer sends data detailing the course of a particular calculation and the efficiency of resource utilisation.”

The supercomputer’s key “customers” are Production and, especially, Technical Research & Development. These days, numerical simulations are used at all stages of the new-vehicle research and development processes, from designing and developing individual structural elements and solutions for the whole car to the final product. They also come into play later on, when enhancements to modernise a particular model are explored. Supercomputing is mainly used in areas such as aerodynamics, impact testing simulations (encompassing body structure functionality tests on the one hand, and occupant and pedestrian protection tests on the other), engines, and simulations of sheet metal drawing, hot forming and casting.

Supercomputing enables engineers and developers to test many times more possibilities than they could in physical tests, and more quickly and cheaply at that. That is not to say that traditional methods have been abandoned altogether, but their scope has been reduced to the bare minimum required. Designers still use clay models, and cars under development are still put through physical tests, a necessity born of the fact that numerous computer simulations are not accepted under current law. Computing simulations can, however, accelerate and streamline development work.

“Using computers, we can run virtual tests and simulations before an actual vehicle becomes available,” says Tomáš Kubr, Head of Functionality Development, Calculations and Series Care. “They allow us to examine places in the structure that are too small to be accessed by a camera or sensor. And we also are able to change various parameters quite quickly and effectively. For example, changing the sheet metal thickness repeatedly in a real vehicle is a complex, protracted and expensive process.”

Yet modern technologies cannot operate without human intervention and support. It is fascinating in what computers can do, but that is not enough. “Humans are irreplaceable,” says Jan Jagrik, Head of the ŠKODA Aerodynamics Department, whose staff enter thousands of calculations into the supercomputer every year. “The combination of this supercomputer and sophisticated software can generate a whole multitude of results and calculate many physical parameters, but it is an expert who has to think about the output and decide, for example, what adaptations and modifications should be made to reduce the vehicle’s drag.”

“Simulations offer a relatively deep insight into what happens during a crash,” explains Tomáš Kubr. “When I run a crash test with a real car, all I can do subsequently is evaluate the results and data from pre-installed sensors. We can’t install sensors everywhere, though. What’s more, if, after evaluating a particular crash test, I decide to test some other parameters, change the car’s speed, and so on, then I would have to destroy another car. With supercomputing, I just change the input data and repeat the test.”

The results speak for themselves. For example, 99% of the crash tests performed in the development of the KODIAQ were done on the computer and only 1% with real cars. Even so, real-car tests are still very important, because they are ideal for checking design solutions and for developing the virtual-test methods further.

“Using these equations, we can describe the airflow as a simple volume, such as a cube,” says Jan Jagrik. “In theory, the result for one cube could be calculated on a handheld calculator, but that would take days. A precise car airflow analysis involves more than a hundred million such cubes, and if we are to carry out such a calculation we need high performance computing.” Aerodynamics is not only about tedious numbers and scientific constants such as the drag coefficient. On the ground, aerodynamics is about helping drivers to travel further on a full tank (or –in the future – on a full charge). Aerodynamics also helps to make vehicle safe preventing dangerous situations that might result from aerodynamic uplift caused by a gust of crosswind, and more.

Air-conditioning and heating
The aerodynamics of a car’s interior is a serious science. Air-conditioning and heating systems are not just about comfort, but are also important for the active safety of a car’s occupants. On a long trip, the driver needs to be alert, responsive to unexpected traffic situations, and neither too cold nor too hot, and the air flowing into the car’s interior must not be a distraction. In the winter, the windscreen and side windows in particular need to defrost and demist quickly to offer a good view of what is happening outside. “Defrosting, especially, is a fairly complex physical process that we could scarcely simulate without a supercomputer,” Jan Jagrik explains. “The layer of ice on a window changes its state of matter twice when hot air is blasted from the heating system: first from ice to water and then from water to steam. It is not easy to model all states of matter in a single simulation. These days, we are able not only to compute all these things, but also to visualise them in 3D.

Keeping to a safety note, a car’s acoustics, too, are not just about comfort. A driver who is distracted by various noises and how intense they are cannot drive safely. “When developing a new car, we need to run a whole range of virtual noise-level tests in a variety of situations, such as acceleration and uneven surfaces,” says Tomáš Kubr. “The problems we address in the passenger compartment are the opposite of those that musical instrument manufacturers have to contend with. They need their products to resonate at particular frequencies to emit tones. We need the exact opposite. We don’t want any resonance at all. And this is an area where supercomputing helps us a great deal.”

Engine design

As preventing fuel leaks in an accident is a matter of no small importance for passive safety, key fuel and injection system components are either reinforced or, conversely, made purposefully weaker in order to define correct breakage areas in the event of a collision. “We also design special reinforcements that protect precarious components against damage in a crash,” remarks Tomáš Král of the EPO – Engine Development Department. “All these structural design measures are, of course, computer designed and tested and subject to computerised impact simulations. Preparing these computer models is no simple matter, but the effort ultimately pays off because simulations can quickly check various engine design solutions. A computer saves time that would otherwise be swallowed up by production operations and the physical testing of vehicles in the development stage. The computer-verified design measures are then tested in a real-car crash test.”