  We present guidelines to estimate the effect of electrostatic repulsion in
sedimenting dilute particle suspensions. Our results are based on combined
Langevin dynamics and lattice Boltzmann simulations for a range of particle
radii, Debye lengths and particle concentrations. They show a simple
relationship between the slope $K$ of the concentration-dependent sedimentation
velocity and the range $\chi$ of the electrostatic repulsion normalized by the
average particle-particle distance. When $\chi \to 0$, the particles are too
far away from each other to interact electrostatically and $K=6.55$ as
predicted by the theory of Batchelor. As $\chi$ increases, $K$ likewise
increases as if the particle radius increased in proportion to $\chi$ up to a
maximum around $\chi=0.4$. Over the range $\chi=0.4-1$, $K$ relaxes
exponentially to a concentration-dependent constant consistent with known
results for ordered particle distributions. Meanwhile the radial distribution
function transitions from a disordered gas-like to a liquid-like form. Power
law fits to the concentration-dependent sedimentation velocity similarly yield
a simple master curve for the exponent as a function of $\chi$, with a
step-like transition from 1 to 1/3 centered around $\chi = 0.6$.
