Pressure standing wave pattern, change cross sectional area

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SUMMARY

The discussion focuses on the behavior of standing waves in a system with varying cross-sectional areas, specifically addressing the formation of nodes and antinodes. Key equations mentioned include the reflection coefficient (R) and the relationship between cross-sectional areas (S1 and S2). It is established that R equals 1 when S2 is significantly smaller than S1, indicating a rigid wall effect, while R equals -1 when S2 is much larger than S1, suggesting a pressure-release surface. Understanding these principles is crucial for solving the problem presented.

PREREQUISITES
  • Understanding of standing wave theory
  • Knowledge of reflection and transmission coefficients
  • Familiarity with sinusoidal waveforms
  • Basic concepts of pressure dynamics in fluid mechanics
NEXT STEPS
  • Study the derivation and application of the reflection coefficient in wave mechanics
  • Explore the behavior of standing waves in tubes of varying cross-sectional areas
  • Learn about pressure nodes and antinodes in fluid systems
  • Investigate the impact of abrupt area changes on wave propagation
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Students and professionals in physics, particularly those focusing on wave mechanics, fluid dynamics, and acoustics, will benefit from this discussion.

snickersnee
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Homework Statement



See pictures. There are 2 parts to the problem but I can probably figure out the second part once I get the first part. [/B]

upload_2015-10-12_17-28-9.png


upload_2015-10-12_17-47-4.png

Homework Equations



Antinodes (minimum pressure) at
upload_2015-10-12_17-43-56.png

Nodes (maximum pressure) at
upload_2015-10-12_17-44-53.png
[/B]

Equation for a standing wave:
upload_2015-10-12_17-46-30.png

The Attempt at a Solution



Other than what I've written above, and that it's sinusoidal, not sure what the problem is looking for here. Any hints would be highly appreciated. Thanks for looking.
 
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I think they are asking you to show where nodes and antinodes form. For example you normally get an antinode at the open end of a tube. However I'm not sure what you get at the transition between the two tubes. I never studied that.
 
CWatters said:
I think they are asking you to show where nodes and antinodes form. For example you normally get an antinode at the open end of a tube. However I'm not sure what you get at the transition between the two tubes. I never studied that.
Hi thanks for responding. Here are the formulas for the reflection and transmission coefficients:

upload_2015-10-15_14-40-36.png

upload_2015-10-15_14-40-53.png

where S1, S2 are cross sectional areas.

R=1 if S2<<S1, a sudden strong area contraction almost acts as a rigid wall.

R=-1 if S2>>S1, in this case the junction acts almost as a pressure-release surface.
 

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