Constrained Damage Detection Technique for Simultaneously Updating Mass and Stiffness Matrices

Summary An experiment to study the interactive effect of large, threedimensional outer eddies on small streamwise vortices was conducted. The TBL near-wall structure was emulated by G¨ streamwise vortices. Outer-region, three-dimensional eddies were shed from the pitch oscillation of an airfoil with sawtooth trailing edge. The three-dimensional eddies included skewed leading and trailing edges and a wallward motion similar to insweeps observedinTBLs.Theinteractioninvolvede uctuationofthenear-wall structure as the outer eddy approached. Violent mixingof e uid and breakdownofthe near-wall structure ensuedas high-speed e uidassociatedwiththe outer eddy arrived.Thissuggeststhat theinsweep associated with the outer region helps trigger the bursting of the near-wall structure in bounded turbulent shear e ows.