A stopped pipe reflects compression from the closed end and rarefaction from the flue.

Evidence

In the stopped pipe, the sequence in Figure 4.15 again begins with a com­ pression pulse being launched into the pipe, but there is no second pulse. Snapshot two shows the instant when the pulses reach the center of the pipe, and the third snapshot the instant when the compression pulse is reflected from the stopped end as a compression pulse (see Figure 4.15) and the summed pressure is a maximum for the cycle of twice the amplitude of the compression pulse. The fourth snapshot shows the compression pulse at the center and in the fifth, the compression pulse is reflected from the flue end as a rarefaction pulse, flipping the air reed from inside to outside the pipe. The sixth snapshot shows the rarefaction pulse halfway down the pipe and the seventh shows its reflection as a rarefaction pulse from the stopped end when the summed pressure there is the minimum for the cycle of twice the amplitude of the rarefaction pulse. The eighth snapshot shows the rarefac­ tion pulse halfway back to the flue end and, by the ninth, one cycle is com­ plete, since events in the ninth and first snapshots are the same. — David Howard, Jamie Angus, coustics and Psychoacoustics, 1197