On the Modelling of a Synthetic Jet as a Spherical Jet

The properties of a flow field of a synthetic jet are studied using hot wire anemometry. The experimental results are compared with an analytical model of a continuous jet derived in spherical coordinates. The radial velocity profiles at various radial distances from the synthetic jet orifice, when scaled appropriately collapse into a single self similar profile. The time averaged flow field can be modeled as an axially symmetric jet, with the replacement of empirical constants obtained from the measurement of the synthetic jet. It is shown that the synthetic jet has a higher spreading rate, and effective viscosity than that of an equivalent turbulent jet with constant mass flow rate. The analytical model in spherical coordinates is shown in this case, to better represent the experimental data than a model derived in cylindrical coordinates.