Experimental Transonic Investigations on Laminar Flow and Load Alleviation

Gabriel Graumann, Johann Krier, Stephan Adden, Bianca Breitsprecher, Ronald C M Cheung, Jonathan E Cooper, Piero Re Fraschini, Loretta Duplessy, Jonathan Loiseau, Michele Averado, Ricardo Gemma, Peter Eliasson, Adam Jirasek

Research output: Chapter in Book/Report/Conference proceedingConference Contribution (Conference Proceeding)


The outcomes of a project to design, manufacture and test a large third-scale transonic
wind tunnel wing model is described. The ETRIOLLA (Experimental Transonic
Investigations on Laminar Flow and Load Alleviation) project was a European Union Clean Sky funded venture which demonstrated natural laminar flow and load control technologies on a large (5.7m) scale wind tunnel model demonstrator under a realistic experimental flight conditions (Mach 0.74). The aerodynamic design enabled both extended laminar flow across the wing and also loads control through the use of trailing edge control surfaces. The scaled aeroelastic design of the wind tunnel model is described. Following its manufacture, the wing was lab tested in order to validate the numerical models and to ensure that the model was safe to test in the wind tunnel. Ground testing consisted of applying a range of different loads to the structure to assess the bending and torsional stiffness, followed a Ground Vibration Test to measure the modal properties. Having updated the Finite Element model, the wing was then tested at a range of different transonic flight conditions. Measurements that were taken included: global forces and moments, lift and drag, laminarity and the transition onset. The experimental program shows that the development of laminarity is proven and that the trailing edge loads control devices improved the aerodynamic efficiency.
Original languageEnglish
Title of host publication2018 AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference
Number of pages10
Publication statusPublished - 7 Jan 2018


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