Abstract
We phrase and solve a problem of particle segregation in a flow of two sizes of spheres in water that is drivenabove by a clear fluid down an inclined erodible bed in a wide channel. The flow is assumed to be steady and fullydeveloped, collisions between particles are assumed to dissipate little energy, and the sizes and masses of the particles are not too different. For particles of the same material with diameters that differ by ten percent, the total particle flux is twice that for a single species with a diameter equal to the average of the two diameters, at least for the angle of inclination that we employ. © 2009 American Institute of Physics.