Getting aero - how riding position affects cyclists
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- čas přidán 20. 06. 2024
- Nicole looks at how a cyclist's body position affects their aerodynamics using flow visualization and computational fluid dynamics.
Thanks to SimScale for sponsoring this video. Check them out and try out some CFD of your own: goo.gl/WXPJZV
Sports Aerodynamics Workshop available here: goo.gl/dej478
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Further resources:
Drag and cyclist leg position: T. Crouch et al., "Flow topology in the wake of a cyclist and its effect on aerodynamic drag," doi.org/10.1017/jfm.2013.678
Tour de France footage:
timpy88, "Tour de France 2015 - Stage 2 @ Utrecht, Marnixlaan", • Tour de France 2015 - ... (Creative Commons licensed)
Music:
Laserdisc by Chris Zabriskie is licensed under a Creative Commons Attribution license (creativecommons.org/licenses/...)
Source: chriszabriskie.com/honor/
Artist: chriszabriskie.com/
Silver by Riot
Special Thanks To:
Ali Arafat
Jean Hertzberg
James Hoskins
Brett Poulton
James Rouse
Netty Zaharia
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FYFD video is written and hosted by Nicole Sharp, Ph.D.
You forgot the superman position
Lol was looking for that comment! :D
During a custom roadbike fitting I was told that in seeking an aero position it is easy to lose breathing efficiency, and when that occurs the reduction in drag is offset, at least in part, by a loss of rider power output. It was the frame designer's expert opinion that a point is reached where a lower position doesn't increase speed, it just loses comfort.
Fuck Yeah Fluid Dynamics! New content! I'll be patiently waiting for your next upload.
Great timing for a video about cycling
Great video, can't wait for more!
Great clip as always Nicole. I was doing this last Friday on my 125cc motorbike. Top speed on a flat freeway is 85kms/h in an upright riding position but I could hold 90kms/h in a tuck courtesy of the V in the drag equation. I wasn't wondering about drag at the time but now I have a good understanding of what's going on. Either way, I'm still basically a moving road block on a freeway with a speed limit of 110kms/h.
I am impressed how much you fit into so little time! :-)
This was so great! Made me nostalgic for our molasses shoot...imagine if we'd done that one til 1am XD
great vid thanks
I wish you tested the difference between Aero TT helmet vs road helmet, thanks for posting this btw.
Would have been interesting to also mention temperature, humidity, barometric pressure as factors having an effect on air density - in addition to altitude as you mentioned. I think these variables can be significant in a time trial.
Higher altitude is inversely proportional D or drag. This is to say, as partial pressure of oxygen (air density) decreases as altitude increases-- so a cyclist rides through the air more easily as altitude increases.
I'm used to forget to comment something, but since I do science videos too and I miss some more comments well, here it is. I love your channel, showing the equations it's important, I think, and I do that on my videos I got, wich, partialy, I got from you.
Showing some equations doesn't mean the audience is familiar with the principles behind it nor they'll be able to handle it afterwards in anything remotely useful, but I do believe that at least some part of the learning process is at least 'learning about' and there shouldn't be many reasons to hide them IMHO, as they usually do some contributions to the understanding of the phenomena. I also like your vids btw. :p
I would love to see an update concerning bicycling hardware and drag, including the frame, wheels, aero bars, and accessories (particularly frame-mounted vs. behind-the-seat bike bottle storage). Ideally, repeat with and without the rider. Helmets may need a separate video.
My concern that much of the "drag reduction" discussed by bike, wheel and accessory manufacturers is little more than hot air, and makes little or no difference in the "real world" of amateur/hobby cycling and racing. I believe that over 95% of all possible drag reduction is accomplished simply by optimizing the ride position. And a non-optimal ride position will see negligible benefit from thousands of dollars worth of drag-reduction hardware and accessories.
Of course, using quality bearings, tires, tubes and proper inflation pressures are also key factors in overall cycling efficiency, but are more difficult and complex to properly evaluate. My heuristic when working with beginner triathletes is to first get a good aero bike fit, next reduce rolling resistance, and only then buy "toys" to meet any emotional needs (the Placebo Effect is very real). I recently gave a premium tube to a friend who flatted on a ride, and he was immediately able to feel a difference in both ride comfort and pedal effort. But that's only an anecdote, not data.
Nothing beats real data, especially if it is organized and presented by FYFD!
Rubbish babbling, just go recumbents and fairings
Hambini does a good video on this
I live in the city, usually small box trucks leave a reliable drag. hatchbacks too. SUVS not so much and drafting Sedans, depends on how big the car is
How much difference would a handle bar fairing make?
How much drag for the spokes?
So if you had a slim item like a fin placed behind the saddle running down the seat tube. Not over the wheel like a tt aero tool box. The blue zone would be further back from the cyclist and the drag force slightly small. Making faster.
I wonder how much better you could visualize that coming thru smoke if you'd separate layers by using different color light by creating such planes like in simulation.
Honestly, we'd planned to use lasers to illuminate specific planes as the cyclist passed through the smoke, but the person who had the lasers didn't make it. So our back-up was to illuminate all of the smoke using our car headlights. I still wish we'd had the lasers, though!
What's about recumbent bikes?
I have a question as I'm not engineering/physics savvy.
Is there ever a case where one would want downforce on a bike? For instance, for high speed descents, sprinting, or cornering?
Hoping someone could answer this question. I'm thinking about 3D printing some stuff to play around with.
@AMPITUP ITTY I agree. As a racer we're always trying to maximize our aero gains. I'm not sure how much more we can do given the current industry standard. Everything looks the same and has a lot of marketing jargon behind it.
I think in most races due to course design it would not play a major role compared to raw power and aeroposition (and drafting teammates ;) over many hours. Although descending and cornering fast can give upper edge in some rare cases. Like Mohorics crazy descent in MilanoSanremo22
nice
Brett’s passage
Lookout Mountain!
can i ask permission to use this video as my story?.....
So I just better get an electric bike rather than a road bike to battle wind? 🙂
When a cyclist is just in the slipstream of another rider, shouldn't the first one bear a stronger drag due to the conservation of enegy principle?
You need take a coarse or already know how to use another brand of CDF to
us sim scale. if you are completely new to CDF world. Then there is no way to learn it form
of the web. The existing tutorials are to help CFD pro make the transition sim scale.
*CFD
People can replicate and test for themselves after watching their workshops, under similar conditions you can try different model. So you don't need past experience to run these simulations and get quite interesting visualization and precise results. It's a good place to start and learn.
Why no recumbents and fairings? Why not explain that?
How to ride aero
Понятно
2:31 is it a he or she or they or wtf is this ? 2 aero fairings on his chest or what?
Awful voice over just stopped watching, after stopping listening