Free Wake Analysis with a Simplified Far Wake for Hovering Rotors

直昇機滯空時之自由尾流場分析

陳慶祥(Ching. S. Chen)

《中國航空太空學會學刊》 29卷3期 (1997/09) Pp. 251-258

https://doi.org/10.6124/TAASRC.199709_29(3).06

摘要

本文利用數值方法來計算直昇機滯空時主旋翼的性能（升力，阻力）及其尾流形狀，此一數值方法結合一組軸對稱，不可壓縮Navier-Stokes方程式的計算和一個升力面的計算方法。升力面方法是用來計算主旋翼葉片上的環流強度分佈，此一環流分佈輸入到Navier-Stokes的計算程式，算出此一環流分佈下的尾流形狀，此一尾流形狀再輸入到升力面的程式，算出此一尾流形狀下的葉片環流分佈，重覆執行此一程序直到環流分佈與尾流形狀都收斂爲止。遠場尾流則是由一半無限延伸的環流圓柱來表示，以節省計算時間。

關鍵字

旋翼機 ； 自由尾流場 ； 滯空

並列摘要

A numerical method based on the axisymmetric, incompressible Navier-Stokes equations is combined with a lifting surface method and a simplified far wake model to predict the performance and vortex wake of hovering rotors. The lifting surface method is used to obtain the circulation distribution on the blade. This circulation distribution serves as an input to the Navier-Stokes calculation to compute the vortex wake under this specified circulation distribution. A semi- infinite vortex cylinder is used as the far wake to accelerate the computation since an analytical expression can be derived which takes the influence of the far wake on the vortex wake into account. An iteration approach is utilized between the lifting surface method and the Navier-Stokes calculation to converge the circulation distribution and the shape of the vortex wake.

並列關鍵字

Rotorcraft ； Free Wake ； Hover