I was thinking about the open water swim in my upcoming HIM. I would think that everyone swimming in the same direction would create a positive current that might help my time a little.
Thoughts?
yeah, but getting kicked in the face probably won’t.
I assume you’ve never studied fluid mechanics?
I don’t know about that, but when there are a bunch of large people doing water aerobics I swear that I feel a cross current and swim noticeably slower.
Right, common strategy is to draft off of someone who is your speed or slightly faster than you. If you’ve never swum open water, you might want to do a forum search.
I have done open water swimming in other triathalons. But I have really only recently really concentrated on anything that can improve my time. I find it more interesting than anything else. I am never going to be an elite. But I love science and technology.
I actually did study fluid mechanics at University. But I am a big believer in actual experience versus theory.
On the bike the power meter has open the ability to better understand different conditions. It is too bad that we don’t have something equivalent in the water. Closes we can get is heart rate and time.
It would be interesting to see the difference in heart rate versus swim time on a course with and without other swimmers. The data would be dirty as the stress with everyone else, getting grabbed, kicked and everything else definitely stresses me.
I understand drafting behind someone else but I was thinking the effect from all the other swimmers beyond drafting behind one particular swimmer.
If you are one person, and you are big enough, you can carry a lot of water with you. Watch the Olympics when the fast freestylers come in for a turn. Two things to note. First is the wall of water that you can sometime see smacking into the wall just after their feet hit, and the second is to watch how deep they go. They go deep to get some undisturbed water to kick, and also to get under all the water they brought with them when they were going the other way. It looks like you were talking about some sort of sustainable current that maintains itself for a long time, and that probably isn’t very likely, but it wouldn’t surprise me if there are temporary benefits that exist for at least 20 seconds after something passes. I’m not sure how people pushing water backwards could effect it though.
I should be able to answer this, we’re SO doing fluid mechanics in Biomechanics right now.
must ponder
will get back to you
I was not thinking a consistent current. I was thinking a net positive overall for the race. In this case a HIM.
Would work needed to complete a HIM swim leg with swimmers be less than without?
My high school team used to do ‘circle 75s’ every so often, which was pretty much getting 30-40 people swimming the perimeter of our rectangular 25yd x 6 lane pool. After a couple hundred yards, you could seriously feel the current we’d created.
And then at the end you’d reverse and go against the current and you’d feel it again, though in a more unpleasant way.
It probably depends on lots of things like the size of the body of water, wind, current, etc as to how much it helps, but it definitely exists. I told my wife I could have done the second lap of IMLP with those swimmie float things on my arms and never swam a stroke-- the current created by the swimmers was so strong it felt like a whirlpool.
I think
In a sense yes. It might be easiest to think of it in the terms of a big blob of swimmers rather than a bunch on individuals. Just like being able to swim within the radius of someone’s wave drag and drafting an individual, you are having a giant set of waves created by the clump of swimmers. By being within the effective radius of the clump, you are affected by the drag (which would acutally make you slower not faster). However when you have so many people disrupting the normal flow of the water, you are displacing large amounts of water and creating that vacuum (not a true vacuum, but I think you’ll get what I mean) in which there is less resistance directly behind an object moving forward against the flow. This is really what drafting (in swimming, running, car racing, etc. is all about). If you are close enough to the person in front of you, you are effectively swimming in the vacuum and not getting caught in their turbulence (and thus able to swim faster for the same level of effort).
