Strong mechanical coupling between the carbon nanotube and the inner streaming water flow

The mechanical coupling between the carbon nanotube (CNT) and the inner streaming water flow is investigated using non-equilibrium molecular dynamics simulations. A strong coupling is found at a critical streaming velocity and such coupling results in the local buckling of single-walled or multi-walled CNTs. The flow-excited radial resonance and the drastic energy exchange-induced radial deformation amplification of the tube contribute to the occurrence of buckling. The tube instability in turn gives rise to the unstable water transport. In contrast to instability occurrence of lamped–lamped macropipes conveying fluid, fully fixing tube’s boundary atoms may eliminate such instability. Combined with the finite element analysis, the effects of the tube size, hydrostatic pressure, van der Waals interaction strength, and the tube wall number on the buckling are discussed. The unusual result is that increasing the hydrostatic pressure weakens the tube’s stability.