2008 年 11 巻 p. 477-486
With the objective of finding the promising contact detection methodology in the physical experiments, assembly of idealized disc particles with different solid fractions were sheared experimentally in the 2D shear flow apparatus. A high speed video camera and subsequent image processing techniques document the positions of the center of particles involved in the flow. This setup also provides opportunity for visual inspection of the collision time and partners. The important characteristics of pre and post collision phenomena were keenly investigated in sparse to dense particle concentration cases so that the precise criteria for each of them could be determined for distinguishing contacts. Based on these observations, new contact detection algorithm is formulated which have three components: finding potential partners of collision, detecting collision partners and finding the duration of each collision. The results obtained from proposed method are compared with the visual observations in the digital video of the physical experiment with the help of motion analytical and particle tracking PTV software. Comparisons of about hundred randomly selected data in different solid fractions and shear rate reveal that the proposed method could detect the contacts with considerable accuracy than the previous methods.