Unsteady Flow and Aerodynamic Noise Analysis around JAXA Landing Gear Model by Building-Cube Method

In this paper, the airframe noise from the landing gear designed by Japan Aerospace Exploration Agency (JAXA) is investigated by incompressible Navier-Stokes flow solver using the Building-Cube Method (BCM) and by the Curle s equation. The BCM is a multiblock-structured Cartesian mesh solver, and the computational domain is composed of assemblage of various size of building blocks where small blocks are used to capture flow features in detail. By using the BCM and the Curle s equation, it is easy to generate a mesh and to perform the flow simulation around the landing gear which has a complex geometry. In this paper, the influence of some tiny components of the landing gear model, including the torque link positions and the wheel cap geometry, on the aerodynamic noise is discussed. It is shown that the flow field and the aerodynamic sound are significantly influenced by the wheel cap geometry whether the wheel had the seal cap or the cap with tear holes. From the comparisons of the pressure fluctuation on the LEG surface and of the streamlines, these phenomena are found to be attributed to the reduction of the vortices and the delay of the flow separation outside the tire caused by the flow induced from the inside to the outside of the tire through the tear holes. The importance of the grid resolution is also discussed.