is it air pressure that causes the shuttle to hang in the air longer in some halls? And if so, then what is a good or proper air pressure for badminton? (talking about feather shuttles of course)
Likely due to multiple layers of air with varying temperatures (thus varying densities). Instead of one single homogenous temperature. Sent from my SM-G965W using Tapatalk
Short answer is no. It's a combination of pressure and temperature which in turn informs the density of the air in the hall that makes shuttles faster/slower in different halls and locations. Different hall layouts in very similar locations also have different effects (drift/floating/hanging etc.) due to distribution of different densities of air (normally more driven by temperature than pressure at the same location since altitude is the main cause of pressure difference), reasons for variance in density would be mainly due to air conditioning settings and distribution (where exactly vents are positioned), occupancy of the hall (people generate heat), lighting layout (again, heat) and alll sorts of factors. The varying temperatures can lead to layering of air as @visor mentioned, where the shuttle can hang in the air as goes from hot to cold air. This gives the idea of 'slow' and 'fast' halls, even if the shuttle speed test leads to the same result. Proper temperatures are as marked on a speed chart such as: https://www.badmintonbay.com/Feather-Shuttlecock-Speed-Chart.html
if you were to drop a shuttle from X metres eg from a balcony at the top of a hall, is there a time it should take to drop? like a table relating height dropped from, with time taken to hit the floor?
Not officially. Perhaps there is research out there that has tried to determine such times. Main problem with a height based speed test would be that you need a relatively high location to drop a shuttle from, and given the shuttle is unlikely to reach it's terminal velocity unless you have a really high balcony, it's likely that the difference between two shuttle speeds will be in order of milliseconds rather than seconds, something quite hard to measure. The existing speed test works well enough for horizontal travel and is easy enough to conduct. If you had a vertical speed test as well, then at best you'll know where a hall is 'fast' or 'slow', but that's about it, since even if the result is different, the rules of badminton are based on horizontal travel and it would be near impossible to switch to vertical speed test in practice (especially for recreational players). In some ways it's like choosing to play badminton with a low ceiling or with a shortened court (I've seen this in small multipurpose sports halls). I'd MUCH rather play in a low ceiling hall than with a shortened court personally! There's just less of an influence is having a slightly lower ceiling (vertical speed considerations), than having the court shortened by 10-30cm (horizontal speed considerations)
Not pressure, density. Generally, colder air will be denser. Humid air will also be denser. Most gymnasia in Alaska in winter are heated, but the relative humidity is so low, even the freshly steamed shuttle will dry and become faster, that is lesser hang times. Also check the diameter of the shuttle. If the wanes open outward after a few hits, this would account for more aerodynamic drag, and therefore the hang time. I did come across a short clip of astronauts hitting the shuttle around, shuttlecock that is.
Does the size of a badminton hall make any difference? and does any particular dimension e.g. height of the roof, make a difference to air density or to any other factors? is humidity and relative humidity required, to factor in, or just relative humidity? Are there any formulae that give the proportion of temperature, humidity, relative humidity, and air density, for a particular speed shuttle to fly at the correct speed(and drop at the correct speed, eg not hanging in the air too long)? Thanks
What you inquire is quite valid, however, beyond the scope of this forum. Go to the nearest uni and find a physics faculty member (professor or teacher). Alternately, find someone who instals those giant windmills, they will also be explain you temperature gradient and geopotential altitufe, and base layer and stuff. For the practical purpose of playing badminton in a club hall, or school gym, or competition arena, yes, the ht of roof will make a difference in establishing a temp gradient. This is easy to visualise. I live in a three storey place, the kitchen is below ground level and the bedroom is top. I will have down booties in the kitchen as it is so cold, however in the bedroom, it is toasty. Hot air rises higher, and the roof, esp when not insulated will develop cold air, which will then sink. In large badminton halls, the same situation, esp when there are a few thousand spectators. Most competition venues are what is called environment controlled. That is, the arena is maintained within some temp range, there is ventilation, air being pumped in, doors being opened and closed, people moving about. So many factors that will be prevalent. Not only this, players will keep on adjusting as these conditions change. The drift for the morning matches may be from left to right, or vice versa, and far to near, or vice versa, and this will change for evening or night matches. The last question is a thesis subject, once again, not within the scope of this forum.
So which venues are slower and which are faster? Japan didn't do well in their home venue in past Olympic, wonder it had any thing to do with the 'speed' of the home venue.
Don’t think so. They would have had access to the hall even before the competition started for ‘testing’.
