Applications and data of generalised dynamic wake theory of the flow in a rotor wake

Abstract

A new co-state method with a finite number of states was recently expanded to be able to calculate the inflow below the rotor disk. The expanded model is derived in a mathematically rigorous way from the potential flow equations. It offers an efficient mean of doing real-time simulation of rotary wing systems and generating the data for design and control purpose. In this study, as an important application of the generalised dynamic wake theory, the new method is used to compute inflow in the wake of a rotor with a finite number of blades. The three velocity components are calculated in the time domain for axial flow. The velocities are plotted at different distances from the rotor disk and compared with the Glauert prediction for axial flow and wake swirl. In the finite-state model, the angular momentum does not jump instantaneously across the disk (as predicted by Glauert), but it does transit rapidly across the disk to correct Glauert value.