HPC-Cloud-based simulation of light-aircraft aerodynamics

The challenge facing Pipistrel was to perform simulations of the flow over its aircraft which were sufficiently detailed to model real physical effects accurately. Such simulations require expensive computer resources which are normally beyond the means of an SME. However, the use of Cloud-based HPC offers the possibility of running such simulations on a pay-per-use basis which is financially viable for an SME. The challenge was therefore to demonstrate the feasibility of such an approach.

The Solution
The use of Cloud-based HPC allowed Pipistrel to run simulations of a higher fidelity than was possible with its in-house systems. These simulations closely modelled real-world behaviour and gave accurate information on how the aircraft would behave in flight. To simulate the flow with the required degree of accuracy, a large computer model was used for the case studies. In doing this, Pipistrel learned how to run, handle and post-process big computations on a Cloud-based HPC system. A typical large model would run in approximately 2 to 3 days on the HPC system. Such a problem would either be too big for the in-house systems or would take too long to run (around 20 to 30 days) to be part of an effective design process. The use of HPC therefore enabled Pipistrel to obtain results of much more complex simulations in a reasonable time. It also offered a cost-effective solution to running such large simulations.

Business Case
Pipistrel needs to simulate the flow of air over the body of an aircraft only occasionally during the design process. It estimates that it is 10 times cheaper to use Cloud-based HPC simulations than have a suitably powerful in-house system which is only used for part of the time. The indicative annual costs of using Cloud-based HPC simulations are approximately €30k compared with an in-house costs of €300,000, which shows that this saving is considerable.

This case study allowed Pipistrel to use HPC for the first time and to learn about its capabilities. Pipistrel ran more demanding, higher fidelity simulations. It gained considerable experience in the use of HPC-based simulation. This experience will help Pipistrel to estimate the time and the cost of such simulations better. This will help them to decide if the use of HPC is justified or not in future projects.
Pipistrel learned that the use of HPC will be very valuable during a design phase of future aircraft. HPC can be used to run much more demanding simulations that improve the fidelity of results. The time needed for such simulations running on an HPC system is roughly the same as the coarser simulations currently run on Pipistrel's in-house cluster. The higher-resolution simulations give more and better data that can be incorporated into each design phase. This both accelerates the design phase and reduces the number of the design cycles.

Organisations Involved
End User: Pipistrel
HPC Expert: XLAB
HPC Provider: Arctur