MASS AND MOMENTUM TRANSPORT IN LONGITUDINAL VORTICAL STRUCTURES IN LIQUID FLOW EXAMPLE OF GORTLER VORTICES

The difference between mass and momentum transport in longitudinal vor tical structures is shown in this paper. The patterns observed by visu alization using laser induced fluorescence are the signature of the ma ss transport, while the flow structures revealed by anemometry show th e momentum transport. Experiments and numerical simulations are perfor med in order to compare the velocity field of the Gortler instability with the mass distribution of a passive scalar. The typical scales inv olved in this problem are discussed with relation to the Schmidt numbe r, in order to compare the size of the observed ''mushrooms'' with the size of the longitudinal Gortler vortices. It is found that the nonli nearities which strongly influence the velocity perturbation do not mo dify the shape and the size of the scalar structures.