In order to analyze the effect of flows on nematic defect nucleation, the isotropic-nematic phase transition processes under shear flows are simulated using second order tensor type theory. The theory includes three major effects of the nematic flows, which are the short and long range order elasticity effects, and viscous flow effect. The point defect structures emerge during the phase transition, as a result of the macroscopic disorder in the molecular orientation field. From the simulation results, it is found that the nucleation of the nematic defect structures is suppressed by the shear flows. The shear flows introduce the extension direction to the nematic liquid crystal materials, and thus the materials evolve to macroscopically ordered systems. Above a certain Ericksen number, no defect structure appears in the materials. Finally, the way to produce defect-free liquid crystal materials is proposed.
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