INVESTIGATION OF NONSTATIONARY GAS-DYNAMICAL CHARACTERISTICS IN THE RESONATOR CAVITY

Mathematical simulation of a nonstationary fl ow of an ideal gas in the resonator cavity is presented. The infl uence of the resonator depth on the amplitude and frequency characteristics of fl ow parameters is studied. The frequency characteristics determined by numerical simulation of a two-dimensional gas fl ow are compared with the results obtained in acoustic linear approximation. The results presented in the work revealed that the nature of the fl ow — the frequency and amplitude of pulsations — is determined by the passage of perturbations along the inner and outer contours of the separating streamline. On increase in the resonator depth, a nonmonotonic increase in the amplitude of fl ow oscillations is noted. There are also dips in the magnitude of the pressure amplitude at the same depth of the resonator or when the frequency of natural oscillations in the resonator is less than the jet oscillation frequency. Oscillations in the resonator occur in the fi rst mode, when the frequency of natural oscillations for the fi rst mode in the resonator corresponds to the frequency of oscillations of the separating streamline. It is shown that, depending on the resonator confi guration, the required parameters and correction coeffi cients will have diff erent values for diff erent fl ow regimes. The paper studies in detail the confi gurations and modes of operation of the resonator and fi nding the discrete frequencies of natural oscillations, as well as presents a mathematical model of the process of resonator self-excitation on the basis of the theory of nonstationary fl ow.
   
Author:  N. I. Sidnyaev
Keywords:  resonator, natural oscillations, pressure, frequencies, fl ow around, geometry, noise, pulsations, technique
Page:  1508