Login
Username:

Password:

Remember me



Lost Password?

Register now!
Socialize
 

Recent Topics
Topic Replies Last Post
Wedding gift... can someone help me to translate it? 6 2018/6/30 20:50
Barga18
Aomori-Ken 0 2018/6/19 10:27
hanzo-tou
Certificates 0 2018/5/8 4:34
schistkicker
Home Project: Shadowbox 3 2018/4/25 21:44
roufus
Ichiba 0 2018/2/21 1:18
Dpinga

Browsing this Thread:   1 Anonymous Users





Sword whistle
村長 :: Sonchou
Joined:
2003/1/27 20:40
From Brussels
Group:
村民 :: Villager
議長 :: Mod
村長 :: Admin
Posts: 267
Offline
Hello,

Could somebody shed some light on the production of sound and its sources when cutting with a sword?
Which physical mechanism is involved here (vortex shedding i suppose...)? Any litterature on this from a more scientific pov?

Thanks alot,

Jan Ramboer

Posted on: 2003/2/10 18:35
_________________
Jan Ramboer
Bujinkan Dojo Brussels

‘It is only when the eyes and the brain get exhausted that there are no lies and you can get the truth’ Thomas Hirschhorn
Transfer the post to other applications Transfer


Re: Sword whistle
Deleted_
OK, this is what I know, if somebody knows better please correct me.

The air is fluid, made of particles. So when something moves, particles of air move out of the way or move in to fill the gap. Particles are banging into each other, that we call vibrations. Membranes in our ears receive those vibrations and recognize them as sound. So hearing is “feeling” vibrations of the material (when you are in water you hear differently).

Frequency is measure of how much something moves or repeats its motion in one second. So particles of air (like of other materials, electromagnetic waves, etc) have their own frequency, depending what caused them. Example. If tweeter produces sound it has very high frequency (we call it high sound) you cannot see the membrane of the speaker “working”, but on bass and his low freq. you can see the membrane “pumping the air”. Also, jumbo jet leaves lot of vibrations behind him, to you can hear the thundering sound. Fighter jet is another story, it is much smaller, and smaller are vibrations, higher sound. Lastly, bullet. Not a good sound at all.

Sword leaves very small gap, but moves very quickly, so air has little space to fill in very quickly. Fast vibrations, high frequency, whistle. Try swinging your sword but turn it for 90 degrees. It will sound like a fan (much more space for particles), and you don’t want to cool down your opponent (maybe you want if you are not an aggressive type ).

Hope I helped.

Posted on: 2003/2/10 19:47
Transfer the post to other applications Transfer


Re:whistle
村長 :: Sonchou
Joined:
2003/1/27 20:40
From Brussels
Group:
村民 :: Villager
議長 :: Mod
村長 :: Admin
Posts: 267
Offline
Thanks for your explanation Merlin.
The reason I want to know is because I am doing research in Computational Aero Acoustics (simulation of sound produced by turbulent flows). The sound of a sword would fit perfectly in my area of research and therefor I am looking for more info. What is the soundmechanism? Does it originate at the kisakki or at the back of the sword? etc...


Posted on: 2003/2/10 20:35
_________________
Jan Ramboer
Bujinkan Dojo Brussels

‘It is only when the eyes and the brain get exhausted that there are no lies and you can get the truth’ Thomas Hirschhorn
Transfer the post to other applications Transfer


Speed
Deleted_
Quote:

Does it originate at the kisakki or at the back of the sword?


It originates at the point because it is the fastest part of the sword when cutting.

Posted on: 2003/2/10 23:03
Transfer the post to other applications Transfer


Re: Speed
村長 :: Sonchou
Joined:
2003/1/27 20:40
From Brussels
Group:
村民 :: Villager
議長 :: Mod
村長 :: Admin
Posts: 267
Offline
Hmmm... this is not necessarily true. Production of sound by turbulent flows is a bit more complex than that. There are several mechanisms possible to produce sound. Speed has an influence on this, but one cannot say that the fastest moving point will be the point where the soundsource is. I can for example imagine that the Hi or the back of sword might be involved too. Usually sharp ends shed vortices (which are well known soundsources) because of detachment of the flow over your object. In this process there can be a multitude of effects playing a role like feedback to name one.

Anybody knows more?


Posted on: 2003/2/10 23:56
_________________
Jan Ramboer
Bujinkan Dojo Brussels

‘It is only when the eyes and the brain get exhausted that there are no lies and you can get the truth’ Thomas Hirschhorn
Transfer the post to other applications Transfer


whistle
Occasional Visitor
Joined:
2003/2/4 11:15
From Ohio, USA
Group:
村民 :: Villager
Posts: 8
Offline
When I did Iaido training in the past, the explaination that I got was that you could tell by the pitch whether or not you were keeping the blade at 90 degrees with the ground.
For what ever that's worth, there ya go!


Posted on: 2003/2/11 9:18
_________________
Scott Reisinger
Transfer the post to other applications Transfer


Re: whistle
Kutaki Postmaster
Joined:
2003/3/17 9:15
From hamburg, germany
Group:
村民 :: Villager
Posts: 212
Offline
hi !
remember the difference between cutting with a blade with and without hi. there is only a very tiny whistle without hi, but a very clear sound when using a blade with hi. the explanation is up to the scientists...

karsten

Posted on: 2003/4/8 21:07
Transfer the post to other applications Transfer







[Advanced Search]


Today's Sponsor