by Sylvio Tessier (Ph.D)
I read a recent article regarding modelling of paddy soil using the CFD-DEM coupling method. The study was conducted by Dr. Long Qi’s research team at the College of Engineering, South China Agricultural University (SCU), Guangzhou, China. For your convenience, I include the following screenshot below, in case you want to read the article as well.
Starting from my Ph.D program, I have been developed interest in seed and fertilizer openers as well as their interactions with soil, aiming to improve the performance of openers. In early days, design of an opener typically needed to go through a long process of prototyping, involving several cycles of design and redesign, fabrication, and testing. That process was time consuming and costly. Now days, computer simulation tools are available to shorten the process. The entire prototyping process can be completed virtually through computer simulation. Several numerical simulation methods have been applied to model soil-tool interaction in developing and improving soil-engaging tools, such as seed and fertilizer openers. Finite Element Analysis (FEA) has been traditionally used in this area. Discrete Element Method (DEM) is a newer numerical method, that is gaining popularity for modeling larger soil deformation.
The aforementioned SCU’s work employed the DEM in modeling the interaction of a fertilizer opener with paddy soil. The challenging issue for modeling paddy soil is its higher moisture content compared with “dry” land. Thus, the researchers in SCU used the DEM in coupling with Computational Fluid Dynamics (CFD). The CFD is an effective numerical method to analyze fluid flow, and therefore, it is suitable for paddy fields containing significant amount of water. The CFD-DEM coupling model developed at SCU was able to predict the soil disturbance characteristics and the soil resistance force of the opener. The predictions agreed well with experimental results. This study and other studies in the literature have demonstrated that the CFD-DEM coupling is a promising method to model the dynamics of soil-machine interaction in agricultural fields with high moisture content.