Two slotted two-dimensional spouted bed units with flexible bed dimensions were used to study the average particle velocity and cycle time of shelled corn, soybean, and wheat in terms of dynamics and scale-up. Circulation of grains was found to be affected by slant angle, spout width, separation distance, horizontal length of bed and the bed geometrical similarity. An empirical equation of solids circulation rate for the two-dimensional spouted beds having draft plates was developed following the principles of dimensional analysis and similitude. Values predicted by the equation agree closely with the data.