Intermittency in two dimensional turbulence

Intermittency of the velocity difference $\delta v_{l}$ and the energy dissipation rate $\varepsilon_{l}$ on scale of $l$ is investigated on the inverse energy cascade range in the forced 2D turbulent flow. Measurements are performed on the freely-suspended horizontal soap film using particle tracking velocimetry. We use the multifractal method to analyze the energy dissipation rate $\varepsilon_{l}$ and calculate the scaling exponent $\tau_{q}$ and the intermittency parameter $\mu_{\varepsilon}$. From high order structure function $\left<\left(\delta v\right)\right>^{p}\sim l^{\zeta_{p}}$, We obtain the scaling exponent $\zeta_{p}$ with integer $p$ and estimate the intermittency parameter $\mu_{v}$. The Komogorov refined hypothesis suggests the relation $\zeta_{p}=\tau_{p/3}+p/3$. This relation agrees with the experimental data up to $p=5$. The deviation for larger $p$ may be due to linear damping in the system that also contributes to the energy flux on large scales.