Its peak performance is 667 Tflop/s and its LINPACK performance is 579 Tflop/s, providing ONERA a return to the TOP500 HPC world ranking. The machine comprises a cooled part classically by circulating ambient air in the bays and a part comprising elements supplied with ice water, allowing to cool the air closer to the computer equipment. The compute nodes, consisting of two Intel Broadwell E5-2680v4 processors with 14 cores running at 2.4 GHz, offer 128 GB of memory and are connected by an Intel OmniPath high performance network.
Compared with the previous configuration, the increases in the power of the computational cores and their number offer an "operational" power 4 to 5 times greater. The contract with NEC foresees a second tranche by the end of 2018, which will enable ONERA to have a total installed peak power exceeding the symbolic threshold of PetaFlop /s (1140 TeraFlop/s).
In the context of noise reduction in civil aviation, performing simulations of this type has a dual interest - predicting the level of perceived noise and understanding the physical mechanisms of noise generation - in order to implement noise reduction methods. The realization of this type of numerical simulations still remains a challenge today and requires very precise calculation methods with low levels of dissipation and dispersion.
The simulation was performed on an unstructured mesh composed of prisms and tetrahedra, with a total number of elements of 3.9 million, which corresponds to a number of degrees of freedom of 78 million per unknown element (pressure, speed, temperature).
This simulation was performed with the Aghora software, on 5768 computing cores of the new Sator cluster for a total of 1.6 million CPU hours. An acceleration factor of 1.8 was measured against the architecture of the previous Stelvio cluster.
Numerical simulation of a subsonic turbulent jet downstream of an aeronautical nozzle (JEAN).