Self-oscillation periods of conical jet aerators with various apex angles

The stable regular self-oscillation modes of penetration of free hollow thin-walled turbulent water jets into water are experimentally studied for conical-jet aerators with various apex angles. A dependence of the self-oscillation period on the apex angle $\alpha$, where $45^\circ\le \alpha\le80^\circ$, is found for $150\le Q\le 550~\text{cm}^3/\text{c}$ and $1\le H\le28~\text{cm}$, where $Q$ is the jet discharge value and $H$ is the elevation of the jet aerator annular nozzle above the water surface.