Abstract: This paper investigates the stability of nitrogen nanobubbles under different concentrations of nitrogen molecules by molecular dynamics simulations. It is found that the stability of nanobubbles is very sensitive to the concentration of nitrogen molecules in water. A sharp transition between disperse states and assemble states of nitrogen molecules is observed when the concentration of nitrogen molecules is changed. The relevant critical concentration of nitrogen molecules needed by the existing nitrogen nanobubbles is analyzed.

Key words: pipe conveying fluid, internal resonance, stability, bifurcation, nanobubble, concentration, stability