Two-dimensional circular cylinder ANDNACA0012 benchmark problems of aero-acoustics computation

With the development of air-transport industry, the noise generated from the civil aircrafts during the process of taking off and landing has been a major concern to people. With the de-velopment of the noise reduction methods of engine, airframe noise has become a major part of large civil aircrafts. The airfoil noise as an important part of airframe noise has been of great interest to the engineering. How to simulate the flow field and acoustic field accurately and how to compute the sound generated by the airfoil are the primary problems. The object of this paper is to calculate the far field sound generated from low Mach number flow around a two-dimensional circular cylinder and NACA0012 using the Lighthill acoustic analogy as the benchmark methods for acoustics computations. In this paper, the flow field and the far field noise are computed respectively. The steady flow field is first simulated by using a variety of Reynold-averaged Navier-Stokes (RANS) models. When the steady flow field is obtained, the time-dependent incompressible unsteady flow is predicted using Detached-eddy simulation (DES) model. The obtained numerical results, such as pressure coefficient and wall friction coefficient, are compared with experimental and computational results from the references. Finally, the far field noise is simulated by using the FW-H solver. The computed unsteady pressure fluctuations on the wall are used as a sound source for the acoustic solver. Different fluent models and different acoustic representative span lengths would make an influence on the computed results. The final is to select the model and acoustic representative span length. The one which could agree well with the previous experiments and computations is what we want.