失速および非失速不均一翼列のねじりフラッタ : 翼配列を考慮したフラッタ抑制効果の評価法

抄録

As an approach to flutter suppression, mistuning effects on fully stalled cascades and unstalled cascades in the torsional mode are investigated, focusing on the fact that the cascade blades fluctuate at a natural frequency brought about through manufacturing processes. Under both stalled and unstalled conditions within the range of normal blade manufacturing imperfection, the larger the coefficent of variation of the natural frequency of a blade group, the more stable the cascade. The flutter suppression effect due to slighter mistuning is expected for stalled cascades rather than for unstalled ones. An irregularly distributed zigzag arrangement gives a fairly high flutter velocity, while an alternating arrangement, which is concluded to be optimum in an unstalled condition, is inferior in the stalled one. Further more, an evaluation method to estimate the flutter velocity from the blade-mistuned arrangement and which takes into account the flutter modal change is proposed.