The Uses Op Coherent Structure

The concept of coherent structure in turbulent flow is a revolutionary idea which is being developed by evolutionary •eans. The aain objective of this review iR to list so•e solid achieve•ent1, showing what can be done by using the concept of coherent structure that cannot be done without it . The nature of structure is described in terns of so•e related concepts , including celerity. topology. and the pheno•enon of coalescence and splitting of structure . The 111ain e•phasis is on the •ixing layer, as the one flow whose structure is well enough understood so that technical applications are now being •ade in proble•s of •ixing and che111Jstry . An atte•pt is •ade to identify so•e conceptual and experi•ental obstacles that stand in the way of prorresa in other technically 1-portant flows, particularly the turbulent boundary layer . A few co••ents are included about the role of structure in nu•erical si•ulations and in current work on •anipulation and control of turbulent tlow . So•e recent develop•ents are cited which suggest that the tiae is nearly right for corresponding advances to occur in turbulence modeling .