PIV study of fractal grid turbulence

The present work describes an experimental investigation of the decay of the wind tunnel turbulence generated by space filling fractal square grids by means of stereoscopic Particle Image Velocimetry (PIV). PIV is severely challenged by measurements of power spectra and measurements of low turbulence intensity flow, and this application involves both. Good statistics require averages over large numbers of frames, and the authors discuss the statistical convergence. Among the quantities to be analysed from the obtained velocity fields are the longitudinal integral length scale, Taylor microscale, streamwise two-point correlation functions, and energy spectra