Study on constitutive models (e.g. flow properties mainly) for particulate solids has been carried out for improved prediction of flow pattern and stresses in silos. The relationship between flow properties of powders and individual particle properties (i.e. particle size, shape and roughness of particle surface etc.) is also being addressed.

Flow properties for silo design are still measured by means of the traditional Jenike tester as shown in Figure 2.

Fig. 1 Uniaxial tester

Fig. 2 Jenike tester after filling and compaction of sample