BUBBLE-INDUCED MODIFICATIONS OF A VERTICAL MIXING LAYER

We analyse the role of coherent structures present in a vertical mixin g layer on the motion of bubbles of various sizes. Then, using the for malism developed in a preview work, we study by means of numerical sim ulation the modifications induced by bubbles on a single vortex and on a plane mixing layer It appears that when bubbles are small enough to be trapped within the vortices they are able to significantly modify the flow field and especially its transverse expansion rate. Simultane ously, a significant reduction of the lateral dispersion of bubbles is observed (C) Academie des Sciences/Elsevier, Paris.