Wing flutter computation using modified spectral volume method for hybrid unstructured mesh

Toward accurate prediction of transonic wing flutter phenomenon, an implicit Spectral Volume method is extended to employ the ALE formulation for moving grid, and also to adopt unstructured hybrid meshes for improving computational efficiency. As a test problem, unsteady flowfield over an oscillating NACA0012 airfoil is computed using the developed code. The temporal variation of the computed normal force agrees well with the experimental data when viscous effect is taken into account. The developed code is then applied to compute the transonic flutter of AGARD 445.6 wing. It is indicated that the computed flutter speed index agrees well with the experimental data at subsonic speed, but agreement becomes worse when the freestream becomes supersonic particularly when viscous effect is absent. The improved computational efficiency of the present SV method using hybrid unstructured mesh is well demonstrated.