Event anisotropy $v_{2}$ of identified particles in Au+Au collisions at $\sqrt{s_{NN}}$ = 27 and 54.4 GeV with STAR

Elliptic flow is one of the most important observables in the relativistic heavy-ion collisions, which can allow us to access the collective properties of the expanding system. In this presentation, we will present elliptic flow of identified particles ($\pi^{\pm}$, $K^{\pm}$, $p$($\bar{p}$), $K_{S}^{0}$, $\Lambda$($\bar{\Lambda}$), $\phi$, $\Xi^{-}$($\bar{\Xi}^{+}$), $\Omega^{-}$($\bar{\Omega}^{+}$)) at midrapidity ($|$$\eta$$|$$<$1) as a function of transverse momentum in Au+Au collisions at $\sqrt{s_{NN}}$ = 27 and 54.4 GeV in the STAR experiment. High precision test of the number of constituent quark scaling of $v_{2}$ and the $v_{2}$ difference between particles and antiparticles will be shown. The $\phi$-meson and multistrange hadrons have small hadronic cross sections and freeze-out early from the medium, therefore can be used to study the energy dependence of partonic and hadronic interactions. Furthermore, the mass ordering of $v_{2}$ is expected to be violated between proton and $\phi$-meson in the low $p_{T}$ range ($p_{T}$ $<$ 1.5 GeV/c) due to their different sensitivity to hadronic phase. These results provide us an opportunity to study the hadronic contributions on $v_{2}$ measurements as a function of collision energy