buisresonantie

Buisresonantie (tube resonance) is the phenomenon by which a hollow cylindrical cavity, open or closed at its ends, supports standing acoustic waves at specific frequencies. These resonant frequencies arise when reflected sound waves interfere constructively, producing stable patterns of pressure nodes and antinodes along the length of the tube.

The pattern of allowed frequencies depends on the tube’s boundary conditions. For a tube open at both ends, pressure nodes occur at the ends and the harmonics are integer multiples of the fundamental: f_n = n·v/(2L). For a tube closed at one end and open at the other, a pressure node at the open end and an antinode at the closed end lead to odd harmonics only: f_n = (2n−1)·v/(4L), where v is the speed of sound, L is the effective length, and n is a positive integer. Small corrections to L (end corrections) and effects of diameter, temperature, and air composition shift the exact frequencies.

Buisresonantie is central to the operation of wind instruments (organ pipes, flutes, clarinets), where control of length and opening produces musical notes. It also matters in engineering contexts such as HVAC ducts, exhaust systems, and acoustic measurement tubes, where unintended resonances can affect performance or noise. The sharpness of resonance is characterized by the quality factor (Q), influenced by viscous and thermal losses and by radiation at the tube ends.

Understanding buisresonantie aids in designing instruments and ducts to achieve desired tonal properties or to avoid problematic resonant amplification.