2D spectra evaluation for single and two phase flows

In this work, 2D spectra evaluation for single and two-phase flows is presented for the streamwise u-fluctuating velocity component. The velocity information was measured at the upper wall of an acrylic rectangular channel at a Reynolds number, Re = 5128 (considering the characteristic length as half height of the channel). A viewing area of 1.28 cm ² in the x-y plane was analyzed using Particle Image Velocimetry (PIV). The 2D spectra were calculated by applying the 2D Fourier transform to the 2D correlation of the u-fluctuating velocity components. It was observed that the energy spectra in two phase flow are less than in single phase flow. Likewise, the energy shifts from large to low wave number when the bubbles are present within the boundary layer.