Experimental Study of 3D Unsteady Flow Around Oscillating Blade With Part-Span Separation

This paper documents an investigation conducted on the aerodynamic response of a turbine blade oscillating in a three-dimensional bending mode under massive tip separation. Flow separation near the tip of the blade was realized by use of a step placed upstream of the blade’s leading edge. Extensive blade surface steady and unsteady pressure measurements were obtained from a test facility with clearly defined boundary conditions for a range of reduced frequency. The experiment is designed to produce detailed and reliable 3D test cases for aeroelastic applications. A complete set of steady and unsteady blade surface pressure measurements is provided for five spanwise sections at 10 %, 30 %, 50 %, 70 % and 90 % of span. In addition, the issue of linearity is addressed. Experimental results demonstrate a predominant linear behaviour of the unsteady pressure response.