Pressure standing wave pattern, change cross sectional area

AI Thread Summary
The discussion centers on understanding the pressure standing wave pattern in a system with varying cross-sectional areas. Participants are trying to determine the locations of nodes and antinodes, particularly at the transition between two tubes. It is noted that antinodes typically occur at the open end of a tube, while the behavior at the junction of different tube sizes is less clear. Reflection and transmission coefficients are introduced to analyze the effects of abrupt changes in cross-sectional area, with specific conditions outlined for strong contractions and pressure-release surfaces. Overall, the focus is on clarifying the formation of nodes and antinodes in the context of the given problem.
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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