  We measure the velocities of the mean flows which are driven by curved rolls
in a pattern formation system. Curved rolls in Faraday waves are generated in
experimental cells consisting of channels with varying widths. The mean flow
magnitudes are found to scale linearly with roll curvatures and squares of wave
amplitudes, agreeing with prediction from the analysis of phase dynamics
expansion. The effects of the mean flows on reducing roll curvatures are also
seen.
