High fidelity CFD simulation of helicopter rotor in forward flight

[@tatotaytoman5934]

the sheer amount of computation necessary just to perform one rotation

[@jidhindharanm.p9351]

Exactly lol..first thing that came to mind just from seeing the thumbail

[@oneracfd8725]

Hello, CFD (computational Fluid Dynamics) requires an accurate mesh for solving the equations of fluid motion. For accurately solving the boundary layer, the first cell on blade wall must have a height of 2 mm for this simulation. For accurately solving the wake and main blade vortex, cells of length 2 cm must be used. This leads to a mesh of 4.1 billion cells representing about 2000Gb of data. Thats why we need to perform the simulation in parallel on HPC clusters. But it enables to predict unsteady loads, transcient phenomena that deteriorate the rotor performance and radiated noise (tonal and broadband to some extent).

[@hubertley939]

Given the amount of work that went into building this model, it would be very interesting to learn more about what specific goal it was built for. Was it the demonstration of sliding meshes, demonstration of software capabilities, or a specific physical aspect? I assume that this is just a prescribed motion of the blades, and not coupled with structural mechanics to analyze forces on the blades, fluid structure interaction, or lift forces. Even as a pure CFD model, this is very powerful in showing the interaction of complex blade motion with the air in the domain. There is of course always the question what software was used to build and run this model, how stable it is, and so on. This represents a ton of work. Excellent video.

[@romainchallenger7465]

this represents a ton of computing time rather

[@robert_hensing]

If you add some explanation at the start instead of in the description, I think this video could really take off... :D As someone with a tiny bit of science background, iso surface is something I can manage, but Q criteria and vorticity magnitude are alien to me. Anyway, I'm glad the algorithm sent me here. It was nice to watch blade angle of attack change and to see the whole thing.

[@oneracfd8725]

Hello, thanks for the comment. We'll try to take it into account for our next videos.

[@Just-Steve]

That leading blade vs trailing blade lift differential was a big deal in the two blade AH-1 Cobra.

[@arezoonajafian797]

Hi Great, How can we simulate this figure in Ansys fluent? If you have any ideas, could you share them with me? tnx. Also How do you put its oscillating movement?

[@kerimsay3148]

I saw blade has conctant flap angle in simulation. I wonder flapping motion is included in simulation or not. I mean Helicopter blade rotates flapping motion and it has different angle with respect to azimuth angle.

[@oneracfd8725]

Hello, blade flapping, lead-lag and pitch variation during rotation are taken into account in this simulation.

[@dhanushkawijethunga]

Is there models to calculate the lift forces acting on the blade. Do manufacturers of helicopters have to do these CFD simulations in order to caculate these things? If that's the case how did they develop earlier helicopters?

[@oneracfd8725]

Hi, yes there are simpler models to get the lift and drag forces for this configuration for instance based on lifting line and vortex wake models. But CFD can provide much more accurate information on boundary layer and vortices interactions. Besides, it can provide data for acoustic propagation.

[@dhanushkawijethunga]

@@oneracfd8725 Thank you so much for uploading these stuff.

[@muhammadfikri-ve8oq]

Use les ? Urans ? Or dns ? Thats amazing

[@christianlabanca5377]

It appears LES

[@oneracfd8725]

Hello, in this simulation RANS model (Spalart Almaras) is used near the blades and LES in the remaining part of the computational domain.

[@klebermarcio1317]

WOW !!!

[@arckrz721]

Wich size of RAM did you use?

[@eeehmeow6899]

We paint the air not ur wall the next level ^,^....

[@Deuce501st]

I'm not sure what I see around 0:21 - 0:32 🤣🤣🤣

[@Just-Steve]

What do you mean?

[@Vipcioo]

RC helicopter model RC pilots have processed 80% of your problems in quite a few years. So I don't see what we have to admire?

[@arezoonajafian797]

Hi Great, How can we simulate this figure in Ansys fluent? If you have any ideas, could you share them with me? tnx. Also How do you put its oscillating movement?