Obviously at some non zero cutter height the flow rate will drop to zero as individual particles become unable to enter the aperture. The form of the graph between the lowest height cutter tested/simulated and the zero flow point is not currently defined.
The results for the conveying of Wheat were almost identical to the Sorghum indicating that the mass flow rate of product, in the case of Wheat and Sorghum is insensitive to the shape effects. The slightly higher density of the Wheat is countered by a lower packing efficiency providing an overall mass flow rate very similar to the Sorghum.