On the basis of the Navier–Stokes equations, the effect of various factors on the temporal development of initial perturbations caused by the start of an annular nozzle blown through with air is investigated parametrically for the laminar model of flow. For the first time, the flow modes at which the initial perturbations accompanying the nozzle start are not damped and pass to the quasi-periodic mode are found in calculations. The Fourier frequency spectrum of pressure pulsations in the center of the thrust wall and the value of the nozzle thrust are determined. The typical pulsating pressure signals obtained in calculations and detected in experiments are presented.