An empirical formula for electrohydrodynamic thrust in the point-to-grid configuration with small electrode gaps

This paper reports an empirical formula that predicts the electrohydrodynamic (EHD) thrust for the point-to-grid configuration with small electrode gap distances. This is accomplished by modifying the classical thrust formula with a loss factor to account for the nonuniform electric field and the drag force on the collector. Experiments are conducted to measure the dependence of the corona current and EHD thrust on the applied voltage for various electrode gap distances. From the experiment results, the proposed formula is empirically derived with electrode gap distance and applied voltage as the independent variables. The proposed formula predicts well the EHD thrust with an accuracy of 40 μN.