Experimental and Computational Investigation of the Flow around a Helicopter Rotor Blade
The paper presents an aerodynamic analysis of the flow around the section of a rotor blade based on the Sikorsky SSC-A09 airfoil. Study was carried out using experimental and computational tools. The experimental part of the investigation were conducted in the 6''x22'' unsteady transonic wind tunnel in the Ohio State University. The test section size is: high 0.56 m (22 inch), wide 0.15 m (6 inch), long 1.12 m (44 inch). A range of the study freestream Mach number is from 0.18 to 1. Tests in the wind tunnel were carried out using two methods: pressure measurements and oil visualization. The numerical simulations were performed based on Computational Fluid Dynamics methods. 2- and 3-dimensional calculations were conducted using ANSYS FLUENT software. In both experimental and computational studies the test article of the research was a section located in the tip region of the main rotor blade of UH-60M Black Hawk helicopter. The model was tested in wide range of angles of attack (between 0 and 20 degrees) and free stream Mach number (0.2, 0.4, 0.6). The paper presents qualitative (a flow visualization) and quantitative (aerodynamic characteristics) results. Numerical models allowed to investigate differences between an infinite wing and a wing with short aspect ratio and also to compare the free-flight condition with wind tunnel conditions.