Role of Transition Modeling in Rotor Hover Predictions

Abstract

The Langtry–Menter transition model is used to predict the aerodynamic performance of three realistic helicopter and tiltrotor blades in hover: the XV-15 proprotor, the joint-service vertical takeoff/landing experimental rotor, and the S-76 conventional scaled rotor. The role of transition modeling in rotor hover predictions is investigated based on comparative studies using the full turbulence model and the transition model. The subsequent predicted transition phenomena are then validated with the experimental data. The focus of this study is to explore three major issues pertinent to rotor hover predictions: 1) the effect of transition modeling on the rotor aerodynamic prediction, 2) rotor prediction at high thrusts or collective angles, and 3) rotor flow characteristics and their influence on aerodynamic performance. Numerical computations indicate different impacts of the transition modeling on predicting the aerodynamic performance for conventional rotors and proprotors.