直升机旋翼的非定常可压缩升力面气动力

本文得出了三元可压缩非定常连续尾迹面条件下直升机等速前飞时旋翼压力分布的解答,使压力偶极子沿尾迹面运动而不沿桨叶的真实轨迹移动以满足尾迹条件,叠加移动压力偶极子获得翼面作复杂运动时三元非定常可压缩的强奇性积分方程,得出了处理强奇性的方法使之成为带强峰值的连续积分方程,并得出了求解该方程的数值解法。在小型计算机上获得的简单算例证明了方程与解法的正确性。

STUDY ON PRESSURE DISTRIBUTION ON ROTOR BLADES WITH THREE-DIMENSIONAL NONSTEADY THEORY OF COMPRESSIBLE FLUID

A calculation of pressure distribution on rotor blades with three-dimensional nonsteady theory of compressible fluid is presented in the case of continuous wake-surface and forward motion of a helicopter at a constant speed. An acceleration potential equation is derived. A fundamental solution of the pressure doublet in an arbitrary motion is given. In order to satisfy the wake condition it is assumed that the pressure doublets move along the wake surface instead of along the actual tracks of blades. By adding the moving pressure doublets, an integral equation of the three-dimensional non-steady compressible fluid with superior singularity is obtained when the blades are in complex motion. The significant effect of compressibility on the higher harmonic pressures is shown in this equation. The kernel function for the integral equation is divided into two parts: one with superior singularity and a continuous function with a strong peak. For the former the Hadamard principal value can be determined as for a wing. With the aid of a proper spline function procedure the function ein is separated from the function, hence it becomes possible to calculate the higher harmonic pressures. A simple typical example is completed on a small computer to justify the equation and the method.