Primary charge effects on prolate spheroids with moderate aspect ratios

► We study the influence of the electric double layer on spheroids with moderate aspect ratios. ► An efficient semi-implicit method based on a splitting of the Stokes equation is proposed. ► There exists a linear relation between the force/torque and the ambient flow field. ► The linear relation can be described by the resistance functions. ► In the low zeta potential regime, approximate formulas can be given.