Good morning everyone ! Sorry being late 🙂 technical problems ahah

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Several EU wind researchers are waiting for the Exascale codes being developed in the US. Do you think this is a good enough strategy? or should EU try to develop its own codes?

Hi. Are the slides of the presentations going to be shared?

There are two DOE funded projects to push wind energy towards exascale, A2E and Exawind, both directed by Michael Sprague, with a total budget of 6 Million US$/per year.How does this compare to the situation in Europe?

Thanks for questions Maria. I'll ask them on your behalf. Luis - we'll ask for that with permission of the authors.

ok

Michelle, have you faced to any simulation case that could not be done to computing limitation??

For more on EoCoE, the Energy-oriented Centre of Excellence see www.eocoe.eu

The project EoCoE is there … together with the network build through the EERA Transversal Joint Programming … to assist in code porting to Exascale using the network of experts available in different HPC centres. This directly addresses the issue stated by Michele on the lack of personnel to tackle Exascale Challenges. So we are not starting from scratch in Europe after all ...

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How many collaborators are working in dedicated mode to this research using codes for HPC systems?

I would like to know what is the effect of using actuator line modelling in the turbulence generation of the turbine wake. Is inflow turb inlcuded in the airfoil tables? Does this have an effect in the overall wind farm simulation?

what type of more local subgrid model, can you ellaborate please?

Is the code suitable for GPUs? How do you plan to take advantage of machines like LUMI? Do you think staying on CPUs is a viable alternative?

Very nice overview, Richard. How do you handle different atmospheric stability and large scale effects like Coriolis force in you wind farm simulations?

Thanks Richard for your informative answer

THANKS!! very nice talk!!

THANKS!! very nice talk!! —> Thanks a lot!

Very nice overview, Richard. How do you handle different atmospheric stability and large scale effects like Coriolis force in you wind farm simulations? —> Thanks a lot! We consider a geostrophic wind to force the simulations and can set the thermal boundary conditions at the bottom and top of the domain. This will allow the atmospheric flow to develop naturally. For details see: https://doi.org/10.1007/s10546-020-00570-5

Thx RIchard.

Is the code suitable for GPUs? How do you plan to take advantage of machines like LUMI? Do you think staying on CPUs is a viable alternative? —> At the moment this code does not use GPU yet. We did already explore GPU for DNS I showed, see https://doi.org/10.1016/j.cpc.2018.03.026. There the GPU code is used on PiZ-Daint supercomputer in Switzerland. When there is shared nodes CPU/GPU one of the main challenges is to ensure that communication is performed at the same time as calculations, so trying to perform computations in a batched way and send over data when part of the calculations are done.

what type of more local subgrid model, can you ellaborate please? --> Anisotropic Minimum Dissipation model, for details see https://doi.org/10.1007/s10546-020-00570-5. The main advantage is even the simplification of the communication patterns that better fit what the remainder of the code uses, compared to the previous subgrid model (lagragian Scale Dependent model) we used

thank you Richard, very nice talk!

I would like to know what is the effect of using actuator line modelling in the turbulence generation of the turbine wake. Is inflow turb inlcuded in the airfoil tables? Does this have an effect in the overall wind farm simulation? —> The inflow is a fully developed atmospheric boundary layer, using concurrent precursor method (http://dx.doi.org/10.1016/j.renene.2014.01.024). The inflow turbulence has a very large effect on the wind farm performance. Essentially higher turbulence leads to more mixing in the atmosphere, which helps the wind turbine wakes to recover faster

thanks!

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thank you Stefan, nice talk. You mentioned wake control using ML, do you mean reinforcement learning? if yes what is the reward policy like?

What about mesh anisotropy (factor 1:10 in LES) for complex terrain? Or do you think isotropic grids would be fine?

thank you Henry!

Thanks!!!

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