AbstractA new hydrodynamic/acoustic splitting method isemployed to predict aeroacoustic tonal noise of self-sustained oscillatory flows over the open cavity at low Mach numbers. Acoustic field is computed using a sixth-order compact scheme and a fourth-order RungeKutta method, with acoustic sources obtained from the unsteady incompressible NavierStokes calculation. First, numerical accuracy of the present splitting method is assessed for the aeolian tone generated by Karman vortex shedding from a circular cylinder at ReD 200 and M 0.3. A direct comparison was made with solutions of direct acoustic numerical simulation (DaNS) and Curle's acoustic analogy. The fundamental mode characteristics of the cavity flows at (i) Re 850 and M 0.077 and (ii) Re 1620 and M 0.147 are examined by the present method, verifying the solution with the experimentally measured sound pressure level (SPL) spectra. A dual tone characteristic observed in experiment (Henderson 2000) for case (i) is also confirmed computationally by the present method.