The acoustic property has much smaller amplitude compared with that of the flow field, so we must use high resolution scheme to calculate it precisely. Optimized high-order compact (OHOC) finite difference schemes, have high resolution and low dissipation-dispersion error, developed for CAA(computational aeroacoustics) problems. The main objective of this thesis is to apply preconditoning method and turbulent model to OHOC scheme. In the low Mach number region, eigenvalues of the system of compressible equations differ widely so that the system becomes very stiff and the convergence becomes very slow. This characteristic can lead to difficulties in computations of many practical engineering problems. Therefore, the time-derivative preconditioning method is applied here to make OHOC scheme more efficient for steady low Mach number problem. Owing to applying the preconditioned method, the governing equation is changed, so new preconditioned characteristic boundary condition is developed for solving preconditioned governing equation. In the high Reynolds number region, the flow is turbulent and DNS(direct numerical simulation) techniques must be used to resolve it clearly. But DNS requires too much time to use, so Spalart-Allmaras turbulent model is used in the high Reynolds flow. In order to validate the preconditioned OHOC code, 2-D nozzle and laminar flat plate are computed and its rapid convergence is confirmed compared with the non-preconditioned code. For the verification of the OHOC code with the turbulent model a flat plate is computed at subsonic, and supersonic regions. Numerical solutions of the turbulent flat plate show good agreement comparing with the Spalding's law of the wall. Compression and expansion corner problems are included in the supersonic speed.
