AN UNFACTORED IMPLICIT MOVING MESH METHOD FOR THE 2-DIMENSIONAL UNSTEADY N-S EQUATIONS

An unfactored implicit time-marching method for the solution of the un steady two-dimensional Reynolds-averaged thin layer Navier-Stokes equa tions is presented. The linear system arising from each implicit step is solved by the conjugate gradient squared (CGS) method with precondi tioning based on an ADI factorization. The time-marching procedure has been used with a fast transfinite interpolation method to regenerate the mesh at each time step in response to the motion of the aerofoil. The main test cases examined are from the AGARD aeroelastic configurat ions and involve aerofoils oscillating rigidly in pitch. These test ca ses have been used to investigate the effect of various parameters, su ch as CGS tolerance and laminar to turbulent transition location, on t he accuracy and efficiency of the method. Comparisons with available e xperimental data have been made for these cases. In order to illustrat e the application of the mesh generator and flow solver to more genera l flows where the aerofoil deforms, results for an NACA 0012 aerofoil with an oscillating trailing edge flap are also shown.