Velocity profiles of an electrohydrodynamic flow generator: CFD and experiment

Abstract The velocity profiles of the electrohydrodynamic flow generator were investigated experimentally and numerically. The generator of a needle-to-cylinder electrode configuration with varying interelectrode distance and supply voltage was studied. Experimental results were obtained with constant temperature anemometry technique and the numerical simulations were performed with Multiphysics Object-Oriented Simulation Environment (MOOSE) framework. The current-voltage characteristic of the device and the relationship between flow velocity and electric current were found out to qualitatively match the results from previous studies. Velocity profiles obtained experimentally and numerically showed varying degree of agreement throughout studied configurations of interelectrode distance and supply voltage. Generally, better agreement was found in cases with lower interelectrode distance, lower turbulence strength and better accuracy of the solution of the electric part of the problem. Some similarities between studied flow and the flow specific for confined jet arrangement were observed, although recorded turbulence intensity values were much higher. Turbulence intensity profile for the lowest interelectrode distance indicated the existence of the shear layer between jet core and the boundary layer. For other values of the interelectrode distance the shear layer and boundary layer could no longer be distinguished. Nondimensional velocity profiles for all investigated configurations showed high degree of similarity in the jet core region, however the similarity was lost in the remaining part of the flow.