Numerical Simulation of Forced Gas Oscillations in a Helmholtz Resonator

A numerical study of gas oscillations in a Helmholtz resonator under the action of a piston oscillating according to a harmonic law near the first and second natural frequencies is carried out. The walls of the cavity are considered impermeable and are maintained at a constant temperature. Air is used as the test gas. The motion of the medium is described by the Navier–Stokes equations for a compressible gas obeying the equation of state of an ideal gas. Changes and features of the flow structure are presented, when the gas is oscillating at the first and second natural frequencies.