Aircraft Simulations Push Computing to the Cutting Edge
Designing an aircraft is one of the more expensive endeavors in the manufacturing business. Complex engineering, strict safety regulations, and high levels of quality control, all conspire to make such development time consuming and labor intensive. It’s no surprise that large manufacturers like Boeing and Airbus have turned to computing, and especially high performance computing, to streamline the effort.
To get a sense of the current state of the art, we asked Guus Dekkers, CIO of EADS and Airbus, to shed some light on the computational challenges involved. In the interview that follows, Dekkers, who will be delivering the opening keynote on this subject at ISC’12 in Hamburg, Germany, explains how HPC is being applied to aircraft simulation today and what the future might bring.
HPCwire: Before coming to Airbus and EADS, you worked in the automotive industry. How do these industries differ in their need for, and use of, high performance computing?
Guus Dekkers: Due to the complexity of both the product and the development process, the aeronautics industry has the need to pre-load and virtualize its development process far more than is the case today in the automotive industry. Whereas in an automotive environment the number of prototypes built has been substantially reduced during the last decade, a new car model will nevertheless still see a substantial number of physical models being built. This compares to a handful of extremely expensive prototypes in the aeronautics industry, with only few — and costly! — capabilities to correct if needed.
Also the number of engineering domains in which advanced simulation is being used is far more substantial than in automotive. Because the aeronautics industry needs to address advanced technical challenges unknown to the automotive industry (ex: lightning stroke, ice accreditation prediction, calculation of dynamic loads during different flight phases, …), and also because the establishment of a physical mock-up is in the automotive industry at times the far easier and efficient way to take design decisions.
HPCwire: Is the use of HPC for aircraft simulations actually enabling engineers to come up with better, more complex designs or is its main benefit cost reduction, via the replacement of physical prototyping and testing?
Dekkers: I would say it is both. Today the engineers do no longer limit themselves to simulate an aircraft’s behavior as a static model, but use the availability of vast high performance computing power to calculate the optimal scenario under different, partially dynamic situations. This allows them to optimize important safety, environmental and performance criteria like fuel-burn, noise, aerodynamics optimizations and performance prediction for multiple scenario’s, which has been impossible in the current precision up until recently. This clearly allows us to design better aircraft.
Certainly, HPC simulation allows as well reducing physical testing — with especially reduced wind-tunnel testing — which helps to slice cost. But ultimately, being [able] to design better products pays off more.
HPCwire: What is the biggest challenge in performing aircraft simulations today? And how is it being addressed?
Dekkers: The challenges are multifold. First and most basic, the compatibility of the simulation software with the hardware architecture. This is why most companies prefer having multiple types of architectures to deal with multiple requirements.
The calibration of the simulation algorithm, its results, and its predictions with real-life also represents a challenge, especially for newer materials like carbon fiber. Here we ultimately have no other option than to validate through physical mockups.
Last but not least, linking both input and output of such a simulation cycle to the “right” aircraft configuration is not evident, that is, how do I make sure the calculations are based on the right digital mockup configuration and how can I assure that its results are reproducible for a very long time-frame?
HPCwire: Are there particular aspects of aircraft design that simulations are particularly good at optimizing?
Dekkers: Traditionally over three-fourths of our HPC capacities have been used for aerodynamic optimizations, which is not a surprise to anyone, I believe. However, we currently see a clear trend shifting its use toward multi-disciplinary design and optimization, aero-acoustics and system integration. This does not mean that the traditional area of using HPC is reducing its usage, but the other use cases simply seem to grow faster.
HPCwire: Can you tell us a little about Airbus’ FuSim program — what it’s about and what are the expectations?
Dekkers: FuSim is for Future Simulation concept. It is a strategic research & technology program launched in 2006 to drastically change the aerodynamic development process.
FuSim objectives are to develop innovative computer-based simulation systems to increase the capability of fluid mechanics design processes by up to a million times, leading to significantly reduced product development lead times, as well as enhanced product optimization through investigation of breakthrough technologies such as flow control. Needless to say, this requires endless computing capacity.
Progress achieved during first phase of Fusim from 2006 to 2011 demonstrated an overall 10^3 improvement in computational fluid dynamics efficiency versus its 2005 basis.
The next big step is Megasim, planned for 2015, which targets another 10^3 improvement in CFD efficiency versus today’s basis, that is, a 10^6 improvement in comparison to 2005.
HPCwire: How important are government and academic partnerships to Airbus and EADS?
Dekkers: Especially in the area of flight physics we have long-lasting partnerships with academic institutes and programs. In this area, I specifically would like to mention C2A2S2E in Germany, Mosart in France, CFMS in UK and DOVRES in Spain.
Our typical work with academia focuses on research methods — how to improve aerodynamics analysis and methods implementation and how to best apply them.
In addition to these initiatives we are looking at an EU funded project, called PRACE, which is federating HPC research infrastructure in Europe, in order to see how the aerospace industry can benefit from European petaflops computing capacity, and eventually access exaflops for the most challenging unsteady aerodynamics and multiphysics simulations.
HPCwire: Which new or upcoming HPC technologies and developments do you think will be most significant for the aerospace industry?
Dekkers: In the area of HPC environments, we will have to deal with the strong growth in I/O management and storage. Between 2008 and 2013, I/O volumes are growing from 5 GB/calculation to 5,000 GB/calculation, which all need to be transferred, stored and displayed. Also the visualization of such data volumes represents a true challenge, not only due to its sheer size but also by having to compress the meaningful data onto available display sizes.
Also handling the physical characteristics of such HPC environments are more and more challenging. Our 200 teraflops container solutions consume several hundred kilowatts in just a couple of cubic meters of space, and need to be cooled in an environmental-friendly way. Here we will certainly need even newer technologies then we have today.
Last but not least, I believe that the efficiency of high performance computing will depend at least as much on the exponential efficiency of the algorithms used, which I would expect to contribute in the same order-of-magnitude as the performance of HPC from hardware innovations. Code must clearly be further parallelized to take benefit from the new architectures — we today still have a lot of “old fashion” code on our systems — and needs to be continuously adapted to take maximum benefit of the newest processor technologies.