$v_{3}\{2\}$ with different $|\Delta\eta|$ gaps is presented in Pb--Pb collisions at $\sqrt{s_{_{\rm NN}}} = 2.76$ TeV. $v_{3}\{2, |\Delta\eta|> 0\}$, $v_{3}\{2, |\Delta\eta|> 0.4\}$, and $v_{3}\{2, |\Delta\eta|> 0.8\}$ are represented by circles, diamonds and squares, respectively. The different panels show the centrality evolution of the measurements Hydrodynamic calculations with MC-Glauber initial conditions and $\eta/s =$ 0.08 , with MC-KLN initial conditions and $\eta/s =$ 0.20 , with Trento initial conditions and temperature dependent $\eta/s$  and AMPT initial conditions and $\eta/s =$ 0.08  are shown in green dot-dash, orange dashed curves, and magenta and grey shaded areas, respectively.