End correction of a closed pipe

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SUMMARY

The discussion centers on the end correction of closed pipes, specifically addressing the formula Delta L = (3d), where d represents the diameter in centimeters. The conversation references Lord Rayleigh's work on sound theory, particularly his 1871 publication which suggests an end correction value of 0.3r, where r is the radius of the pipe. Various values between 0.3r and 0.6r have been proposed, but no universally accepted standard exists. Participants emphasize the importance of precise calculations in applications such as organ pipe manufacturing.

PREREQUISITES
  • Understanding of fluid dynamics principles
  • Familiarity with acoustic theory and sound wave propagation
  • Knowledge of hydraulic radius and diameter concepts
  • Basic mathematical skills for applying formulas
NEXT STEPS
  • Research Lord Rayleigh's "Theory of Sound" for historical context on end correction
  • Explore the concept of hydraulic radius in fluid mechanics
  • Investigate various experimental methods for measuring end correction in pipes
  • Learn about the differences in end correction for closed versus open pipes
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Acoustic engineers, fluid dynamicists, and organ builders seeking to optimize sound production in closed pipes.

Zoro
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Homework Statement



Is there a scientiically approved method for end correction of a closed pipe.

Homework Equations

The Attempt at a Solution


The formula used is Delta L = (3d) where d = diameter in cm.
 
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Zoro said:
Is there a scientiically approved method for end correction of a closed pipe.

i think there are theoretical analysis of the correction by Rayleigh and others and one will have to go through their work...as people who are manufacturing the organ pipes do take care for the exactness of the frequencies to be excited by the pipes

for example one can see;
Lord Rayleigh, Theory of Sound, Vol II, §314 (Dover, NY, 1945 [1896] ) p.201 ff.
http://www.larrylawson.net/Journal/Pipe1V5N2.pdf
 
Zoro said:
The formula used is Delta L = (3d) where d = diameter in cm.
Check the correction term ;
perhaps it is 0.3 r or 0.6 D where r and D are radius and diameter of the pipe respectively.
 
According to wiki there is not:

There is no scientifically proven and accepted value for the end correction of a resonant tube, various values ranging from 0.3r to 0.6r have been suggested from numerous disparate experiments. Lord Rayleigh was the first experimenter to publish a figure, in 1871: it was 0.3r.

Take from that what you will.
 
drvrm said:
Check the correction term ;
perhaps it is 0.3 r or 0.6 D where r and D are radius and diameter of the pipe respectively.
Did you mean "0.6r or 0.3D"?
 
haruspex said:
Did you mean "0.6r or 0.3D"?
i might have made an error; pl. see
https://en.wikipedia.org/wiki/End_correction

c269831971eee08a97469fb93611d015.png
is known as end correction, which can be calculated as,

  • for a closed pipe (with one opening):
a802f05e26b2cb3a5aa14b1810417721.png
,
where
4b43b0aee35624cd95b910189b3dc231.png
is the hydraulic radius of the neck and
f623e75af30e62bbd73d6df5b50bb7b5.png
is the hydraulic diameter of the neck;

  • and for an open pipe (with two openings):
d9404c5ca84cb12b0c2c3bcc7984b81a.png
.
 
is it 0.3 d where d is in cm or m
 

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