Technology to predict acoustic far-field disturbances in the case of calculations in a rotating reference frame

Abstract

The paper discusses the use of the Ffowcs Williams–Hawkings method to predict far-field acoustic disturbances in the case of near-field calculations in a rotating reference frame. This formulation is particularly convenient for the simulation of a single rotor. If the rotor velocity is sufficiently high, in Farassat’s classical 1A formulation, when using the control surface associated with the grid, singularities arise in the expression under the integral sign. In order to avoid them, we use an axisymmetric control surface and consider it fixed in the absolute reference frame. This makes it possible to reduce the additional difficulties caused by rotation and interpolate and calculate the derivatives with respect to the angle.