Scalar power spectra and turbulent scalar length scales of high-Schmidt-number passive scalar fields in turbulent boundary layers

High-Schmidt-number passive scalar fields resulting from an isokinetic release in a turbulent boundary layer are characterized via turbulent scalar length scales, fractal geometry, intermittency, and power spectrum in the inertial-convective (I-C) and viscous-convective (V-C) regimes.The analysis indicates that the V-C scaling behavior deviated significantly from Batchelor's -1 scaling law for all Reynolds numbers and initial nozzle diameters. The scalar fluctuation intermittency, which generates nonGaussian tails in the PDFs of the scalar fluctuations and produces a large dissipation rate, explains the steep spectral slope in the V-C regime.