Originally Posted by nordell

I suggest you review details from our ROCKY DEM website that illustrates the contact physics between multiple (millions) particles of varying sizes and shapes and contact mechanics (dry to full sticky) and with gas and fluid interactions. This work has been in progress since 1995. Advances in comminution rock breakage, dust emissions, surface wear mechanics, energy dissipation or absorbtion and many other features can be observed.

You can go on You-Tube and see many such models that have a long tradition in modeling granular flow from basic principles.

Since last year when I was involved in the design of a new mass flowrate meter (was based on impact plate) for measuring flowrate of grain flow in flour mill industry, I had studied its theoretical base further (also touching back to my previous research knowledges in fluid and gas flows, particularly chaotic flows analytically), I had seen DEM, FEM, etc computational modellings such as your ROCKY and I respected much to the efforts being spent for such granular flow modellings which use too many input parameters such as shapes of particles, their variations, etc etc. This is so because there aren't some simple physics models for granular flows as types of flows of these granulars vary a lot, with many different factors. I am sure such computational models are the only useful tools at this stage and we don't know if a good physics model with its analytical form which will describe a big group of granular flows will be found by researchers or not as this flow type is really complex. Some months ago, I read a scientific paper by a theoretical physican who claim this granular field must be handled in a new state of matter, 4th state of matter after solid, fluid and gas. Maybe, he is correct. Modelling each granular flow phase by resembling them to fluids or gas will be limited to certain applications only and efforts spent for modelling different types of flows will be a lot. I've not been in this granular flow and its engineering field, but, I see that engineering studies in this field are largely based on experiences of engineers in the field rather than scientific studies at universities by high! level scholars who have probably ignored this "low!" level of science in grain mills. As someone who has worked chaos even in pure mathematic ways, now, I found this granular flow field is really attractive as chaos can be seen even in the first order, in varying shapes of particles. While you are already studing and writing code of a DEM model, I have an idea that may simplify your model a little more? Have you used fractal geometry in your model? (I am saying this without reading anything else. Maybe, someones already used.) As you can know/think of, a fractal geometry in your model may decrease degree of freedom in shape functions if there are symmetries (tool for searching such symmetries is in group theory in math.) ■