Algorithm of Mesh Deformation for Accounting Cyclic Blade Control and Blades Flapping in the Problem of Helicopter Main Rotor Modeling

Abstract

This paper presents the developed algorithm for numerical grid deformation for solving the problems of modeling the flow around the helicopter main rotor in the horizontal flight mode with allowance for flapping movements and cyclic changes in the angle of the blade installation. In general, this algorithm can be applied to simulate the aerodynamics of solid bodies deviating from its initial position at angles up to 90 degrees in the vertical and horizontal planes relative to the origin point, and also performing a rotational motion at an angle up to 90 degrees around the axis through the center of coordinates and the body mass center. The first part provides a brief overview of the existing methods of the computational grid deformation for solving various problems of numerical simulation. These include methods for rebuilding the grid, moving grids and "Chimera" grids. The second part describes the algorithms for allocating of grid deformation and for finding the final coordinate of the computational grid nodes in the presence of a predetermined blade control law. The equations of the deformation zones shape in numerical grid are given. The influence of variables on zones sizes is shown. The third part presents the results of methodological calculations confirming the performance and limitations when choosing mesh deformation zones. The influence of the size and shape of the deformation zones of the numerical grid on the quality of the mesh elements is also shown. This work is methodical in nature and is a preliminary stage in the numerical modeling of the flow around the helicopter main rotor taking into account the automatic main rotor balancing and blades flapping.