Unsteady cooperative flow in compression system

When there are several bodies with relative motion in a flow field, such as the flow in the compression system of modern aero-engine, the flow field will have certain special features, one of which is that the time-space structure of such multi-bodies unsteady vorticity flow field would be either of unsteady natural flow (UNF) pattern or of unsteady cooperative flow (UCF) pattern. If we further examine the aerodynamic design system of aero-engine, there is no mechanism for the unsteady cooperative flow to occur, in other words the flow field must be of the unsteady natural flow type. If certain technical measures can be adopted to transform UNF into UCF, the aerodynamic performances will surely be improved. This is the main task the author and their colleague have been devoted to and the results are reviewed in the present paper with emphases laid on basic ideas, technical approaches and experimental verifications.