Hydrodynamics

[Azrael3000]

Hi all,

as one can gather from my introduction thread I'm doing a PhD in computational fluid dynamics. I'm using quite a specific method which should possible allow the simulation of shape-changing, moving objects.

Thus my question, would it be of interest for the freediving community if somebody analyses the hydrodynamics involved? One example could be the simulation of a diver with different types of fins. In the very long run this could maybe help the evaluation of new designs.

If there is any such interest I might try to find some spare time to implement such a feature. If not, well then I'll use it to do some tables

Cheers,
Arno

 

[trux]

Hi Arno, and welcome to DB! Definitely, this topic is very exciting. In fact my club colleague, a long time friend, and the president of our club Cyrnéa in Lyon, France is a professor of mechanics of fluids here in Lyon, and it is since several years he promisses to launch a freediving specific study. Somehow the right motivation, or the time is still missing, so he did not do it yet. And since you tell you are partially living in France too, perhaps you could contact him and team up with him. There are already some ideas. If interested, please, send me a PM for the personal contact - I do not want to post it here publically without his consent.

 

[efattah]

The best benefit you can give is to solve for a fairing. In other words, what shape modification to the head, legs, or torso, will reduce the drag of a person the most?

 

[Fondueset]

Definitely - though I'd advocate also for a non-fairing approach as well.

 

[Azrael3000]

@Trux: I will write you a pm

@Eric: Do you mean with or without body movement? The latter I hope to be able to do in maybe 2 to 3 months time.

@Fondue: Any specific ideas?

In general, this partly coincides with the work I need to do for my PhD, so that is good because I can work on it during office hours. Moving bodies is another story. I will do the programming after I've done my more or less daily (c)o2 tables. If some interesting results come up I'm happy to put a paper together and submit it to a journal. Depending on the amount of collaboration I can add some of you as co-authors if desired.

In case somebody runs around with knowledge of Blender let me know. I have some questions for him.

 

[Apnea Costa del Sol]

Hi Arno and all,

I new at the forum but fascinated about its content!.

Aron, by this time you might well finished your phD and I wonder if you did move forward (i.e. published) or not. I was planning to use SPH (Smooth Particle Hydrodynamic) to analyse the drag during free-falling with arms extended (like super man) and arms along the body. In principle is without movement (i.e. just freefalling not finning). Intuitively this might well change the phase of wave generated and, since we all free fall at about same speed, the optimum will varies with the freediver height.

Looking forward to hear from you all and congrats for a great forum.

 

[Azrael3000]

Hi buddy.

As a matter of fact I am just days of submitting my PhD. Unfortunately, I never got around to do anything freediving related and the reason for that is twofold. First, the Reynolds number is rather high requiring an appropriate resolution. Secondly, SPH really is not the best method to attempt such a simulation. If I had too much spare time on my hands plus the computational ressources then I'd go with some Finite Volume code (openFOAM, Code_Saturne) and then do a URANS simulation. If you want me to expand on that let me know and I'll happily do so.

Cheers,
Arno