Pressure standing wave pattern, change cross sectional area

Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
2 replies · 2K views
snickersnee
Messages
30
Reaction score
0

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.
 
Physics news on Phys.org
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.