L09_a - STANDING WAVES IN AN AIR COLUMN (Wind Instruments)...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
STANDING WAVES IN AN AIR COLUMN (Wind Instruments) Sound waves (longitudinal) reflect from open and closed tube ends Two possible boundary conditions Can also describe wave in terms of PRESSURE or DISPLACEMENT AT A CLOSED TUBE END No longitudinal displacement of air next to end DISPLACEMENT NODE Large amplitude pressure changes PRESSURE ANTINODE AT AN OPEN END Air free to oscillate DISPLACEMENT ANTINODE Air is free to move so pressure does not change PRESSURE NODE Real boundary at the end of an open tube is outside by ~0.6 x tube radius o End correction We will use DISPLACEMENT to describe normal modes of an air column.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
HOW DO WE “REPRESENT” STANDING WAVES IN AN AIR COLUMN? Represent AMPLITUDE OF LONGITUDINAL DISPLACEMENT by width of “loops” in diagram o CAREFUL: there is no transverse character to modes o Each “loop” in the mode diagram is λ /2
Background image of page 2
LONGITUDINAL MODES OF A TUBE OPEN AT BOTH ENDS
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 7

L09_a - STANDING WAVES IN AN AIR COLUMN (Wind Instruments)...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online