Abstract
Space-time correlations and power spectra of velocity fluctuations are measured in two-dimensional turbulent flows through curved and straight channels. Noticeable differences are seen between the experimental results of the two channels. While each effective power spectrum in the straight channel has only one maximum, each of those in the curved channel has two maxima on both sides of a wave number corresponding to the dissipation length. The spanwise correlation of radial velocity fluctuations in the curved channel takes a large negative maximum at an interval of about half the channel width. The streamwise integral length scales on the outer-wall side of the curved channel increase to about ten times those in the straight channel. These results indicate that intensive large-scale eddies which are unsteady but resemble Taylor-Gortler vortices exist in the curved channel.
