Global numerical prediction of bursting frequency in turbulent boundary layers

The frequencies of the bursting events associated with the streamwise coher ent structures of spatially developing incompressible turbulent boundary la yers were predicted. The structures were modeled as wavelike disturbances a ssociated with the turbulent mean flow using a direct-resonance theory. Glo bal numerical solutions for the resonant eigenmodes of the Orr-Sommerfeld a nd the vertical vorticity equations were developed. The global method invol ves the use of second and fourth order accurate finite difference formulae for the differential equations as well as the boundary conditions. The pred icted resonance frequencies were found to agree very well with previous res ults using a local shooting technique and measured data.