Computational Modeling of Hovering Rotor and Wake Aerodynamics

Abstract

Steady-state Reynolds-averaged Navier ‐Stokes computations are presented for a range of UH-60A model-rotor testcasesinhover. Thecomputationsaredesignedto assessgrid-related effectson thenumericalresultsandemploy 1)structuredoversetgridswithhighresolution ontherotorblades,2 )asystematicvariationofgridresolutioninthe rotor wake, and 3 ) a systematic variation of outer-boundary locations. Computed rotor performance values agree very well with experimental measurements and show little sensitivity to either grid resolution or outer-boundary locations. However, the computations uniformly overpredict the blade sectional thrust near the rotor tip. This overprediction of blade tip thrust is explained by an analysis of the circulation distribution in the computed rotor wake system.