Effect of Concentrated Roughness on Transition Location at Transonic Speed: from Infrared and High Frequency Pressure Measurements to MDOE Approach

This paper describes the Design of Experiment to study the laminar­turbulent transition phenomenon on a 10° AEDC cone in Transonic­Supersonic regime. In particular, the effects of several parameters (as concentrated roughness height, roughness position, Reynolds number and Mach number) on the laminar­turbulent transition were measured. The large number of parameters that were considered, made this activity very complex and expensive to study with a typical experimental approach. As consequence, a Modern Design Of Experiment approach was adopted to develop highly efficient experiment designs yielding results to within a specified accuracy and, at the same time, saving resources in terms of costs and time consuming. A secondary objective of this activity is evaluate the correlation between infrared measurements and high frequency pressure measurements for transition analysis.