Structure of iso-scalar sets

An analytical framework is proposed to explore the structure and kinematics of iso-scalar fields. It based on a two-point statistical analysis phase indicator field which used track given volume. The displacement speed iso-surface, i.e. interface velocity relative fluid velocity, explicitly accounted for, thereby generalizing previous equations dedicated in two-phase flows. Although this applies many transported quantities, we here focus passive scalar mixing. Particular attention paid effect Reynolds (the Taylor number varied from 88 530) Schmidt numbers (in range 0.1 1), together with influence flow forcing. first found that diffusion iso-surface tangential direction predominant, emphasizing primordial curvature speed. Second, appropriate normalizing scales for statistics at either large, intermediate small are revealed appear be related radius gyration, surface density standard deviation mean curvature, respectively. Third, onset an ‘scaling range’ sufficiently large observed. scaling exponent complies fractal dimension 8/3. A also observed transfer fields scale space whose can estimated by simple arguments recent closure Corrsin equation. Fourth, effects or forcing different terms budget highlighted.