بررسي نظري اثر حضور روتور در ايجاد فشار غيردايم رو ي بدنه ي هليكوپتر

STUDY OF UNSTEADY AIRLOADS INDUCED ON A HELICOPTER BODY DUE TO ITS MAIN ROTOR

The unsteady, incompressible, inviscid and irrotational flow field around a helicopter model in forward flight has been treated numerically, based on singularity element methods. A full three-dimensional modeling of the body, the rotor and its wake is used, in order to study the effects of an operating rotor on the in-flight unsteady airloads induced on the body. This model consists of an unsteady source panel representation for the body and a doublet distribution for the rotor and its shedding wake. A comprehensive code has been developed, based on an iterative coupling method and used for a single rotor helicopter model. Here, the unsteady pressure signatures on the body surface have been calculated due to two known phenomena, i.e blade passage effect and close wake interaction. The computed results show that this code has a fairly good capability for prediction of the complex flow field around a helicopter.