Evaluation of Travelling Vortex Speed by Means of Dynamic Mode Decomposition and Residual Vorticity

Abstract

The article deals with the analysis of synthetic jet flow field by means of dynamic mode decomposition (DMD) method. The speed of travelling vortex ring which is connected with synthetic jet creation is evaluated using the wavelength identified from DMD modes. Vortices are identified in the DMD modes by using residual vorticity which allows to identify regions in the flow field where fluid particles perform rotational motion. The analysis is based on the data from the numerical simulation of synthetic jet into quiescent air by using ANSYS Fluent code. The regime of synthetic jet with Re = 329 and Stk = 19.7 is chosen. An increase in the vortex speed close to the orifice and then the decrease is observed with maximum reaching almost one and half of averaged blowing orifice centerline velocity.