The calculation of the sound generated by turbulence and the scattering of sound by rigid bodies have many applications in the prediction of engine noise and airframe noise, and in the assessment of the acoustic shielding capability of aerodynamic bodies. Until recently, most predictions relied on simple empirical models or, in special cases, analytical solutions. Alternatively low-order numerical schemes were used in numerical simulations that needed very fine grids and long execution time. Recent advances in algorithm development and computer capabilities have meant that direct simulations of these phenomena are now feasible. This has led to an interest in a new field of study called "computational aeroacoustics". The objectives of the present study include the use of high-order algorithms and the efficient numerical simulation of acoustic wave scattering by solid bodies.;A high-order, high-bandwidth Dispersion-Relation-Preserving (DRP) scheme has been used in this study. Non-reflecting boundary conditions are used for the outer boundaries of the computational domain. A method to treat solid boundaries is proposed in order to simulate acoustic scattering by solid bodies. This is the Impedance Mismatch Method (IMM). In this method the solid wall is simulated using a wall region in which the characteristic impedance is set to a different value from that in the fluid region. A conventional method to implement solid wall boundary conditions has also been examined and compared with the IMM. The IMM reveals a lot of advantages over this conventional method. These include its simplicity of coding, reductions in computer time, and its easy treatment of curved boundaries. The IMM has been used to compute acoustic scattering by two- and three-dimensional bodies. In the 2-D case, numerical simulations have been carried out for scattering by an infinite wall, with and without a mean flow, a finite plate, and cylinders. For the 3-D case, scattering computations for a sphere and a cylindrical shell have been conducted.
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