Comparison of different Inflow Models for Intermeshing Rotors

Abstract

New inflow models have been introduced in the literature for multirotor systems with the goal to include inter-action effects between the rotor. While these models have been validated for some rotor configurations, a validation for intermeshing rotor configurations has yet to be presented. This paper gives an overview over some of the existing inflow models applicable to intermeshing rotors. Flight test data is used to compare the hover trim state calculated using different inflow models: The Pitt-Peters model, the Combined Momentum Theory Simple Vortex Theory (CMTSVT) model and a simple inflow coupling introduced in a paper from Padthe et al. The comparison of flight test and simulation prediction shows that for intermeshing rotors, interaction effects must be included in the inflow model to obtain accurate rotor power and collective angle.