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Dear BIOMCH-L subscribers!
As far as I know, some of you are actively involved in wind-tunnel testing of
elite-cyclists and I would appreciate your help.
In our biomechanics undergraduate courses we teach a little cycling biomechanics and
regularly come across the topic of wind-tunnel testing and the problems involved. From
our own experience we know, that wind drag data (F) is always very erratic (i.e. no
smooth or constant data can be read). Especially when a cyclist is pedalling large
oscillations of the recorded drag-force occur.
When looking at some video footage (e.g. "Science of Cycling - Lance Armstrong 2005",
http://www.youtube.com/watch?v=nzrhPUTvCS4 around 5:04 min) it can be seen, that there
is a certain value read out, that is quite constant (or at least constantly dropping in
this case). Some other scenes show constant live read-outs (Only for the TV-cameras? Are
these data usually post-processed to obtain interpretable data?).
So my question is:
- How are the data filtered to obtain such "good" data?
- Is there a special algorithm? (band-pass corresponding with cadence? low-pass for the
noise due to the chaotic nature of aerodynamics?)
- Is there literature where these algorithms (in case they exist) are described?
Thank you! Your help is highly appreciated.
A summary of the responses will be posted.
mit freundlichem Gruß / best regards
Stefan Litzenberger
--
DI(FH) Stefan Litzenberger
University of Applied Sciences Technikum Wien
Deputy Head of Department of Sports Engineering & Biomechanics
Hoechstaedtplatz 5
A-1200 Vienna
Austria
Tel: ++43 1 3334077 - 377
Fax: ++43 1 3334077 - 369
mailto:litzenberger@technikum-wien.at
http://www.technikum-wien.at/
As far as I know, some of you are actively involved in wind-tunnel testing of
elite-cyclists and I would appreciate your help.
In our biomechanics undergraduate courses we teach a little cycling biomechanics and
regularly come across the topic of wind-tunnel testing and the problems involved. From
our own experience we know, that wind drag data (F) is always very erratic (i.e. no
smooth or constant data can be read). Especially when a cyclist is pedalling large
oscillations of the recorded drag-force occur.
When looking at some video footage (e.g. "Science of Cycling - Lance Armstrong 2005",
http://www.youtube.com/watch?v=nzrhPUTvCS4 around 5:04 min) it can be seen, that there
is a certain value read out, that is quite constant (or at least constantly dropping in
this case). Some other scenes show constant live read-outs (Only for the TV-cameras? Are
these data usually post-processed to obtain interpretable data?).
So my question is:
- How are the data filtered to obtain such "good" data?
- Is there a special algorithm? (band-pass corresponding with cadence? low-pass for the
noise due to the chaotic nature of aerodynamics?)
- Is there literature where these algorithms (in case they exist) are described?
Thank you! Your help is highly appreciated.
A summary of the responses will be posted.
mit freundlichem Gruß / best regards
Stefan Litzenberger
--
DI(FH) Stefan Litzenberger
University of Applied Sciences Technikum Wien
Deputy Head of Department of Sports Engineering & Biomechanics
Hoechstaedtplatz 5
A-1200 Vienna
Austria
Tel: ++43 1 3334077 - 377
Fax: ++43 1 3334077 - 369
mailto:litzenberger@technikum-wien.at
http://www.technikum-wien.at/