Experimental Validation of CFD Modeling for Narrow Tillage Tool Draft

Total energy requirement of a vertical narrow tool is a function of different soil-tool interaction components like soil parameters, tool parameters and system parameters. Dynamic analysis of tillage-tool modeling concerns soil deformation due to soil shear failure caused by mainly soil-soil interaction, soil-tool interaction and acceleration energy. Soil bin tests were conducted to validate tool draft predictions from numerical modeling using computational fluid dynamics (CFD). Three dimensional simulations were carried out using fluid dynamics approach considering soil as a Bingham material. Soil dynamic parameters such as soil viscosity and yield stress were determined by a strain rate controlled torsional Soil Rheometer, developed in the Agricultural and Bioresource Engineering Department, University of Saskatchewan. Numerical predictions of tool draft were observed with 40 mm wide vertical tool operating at four different depths of 40, 80, 120, and 160 mm. The tool was operated at four different operating speeds of 1, 8, 16 and 24 km h-1 in clay loam soil with two moisture contents of 14 and 20%. Soil bin experiments were conducted with the same tool configurations, soil conditions and operating speed. Draft values predicted by the CFD modeling were highly correlated with those obtained from soil bin experiment.