Experimental observation of 1/f noise in quasi-bidimensional turbulent flows

We report the experimental observation of 1/f(alpha) noise in quasi-bidimensional turbulence of an electromagnetically forced flow. The large-scale velocity U-L exhibits this power-law spectrum with alpha approximate to 0.7 over a range of frequencies smaller than both the characteristic turnover frequency and the damping rate of the flow. By studying the statistical properties of sojourn time in each polarity of U-L, we demonstrate that the 1/f(alpha) noise is generated by a renewal process, defined by a two-state model given by the polarities of the large-scale circulation. The statistical properties of this renewal process are shown to control the value of the exponent alpha. Copyright (C) EPLA, 2015