Experimental Design for the Validation of Extended Hybrid Laminar Flow Control and Transition Prediction in Complex 3D Flows

Kurzfassung

This study presents the design of a wind-tunnel experiment intended to test the validity of linear stability theory in a fully three-dimensional flow, as well as to demonstrate the feasibility of boundary-layer suction within the adverse-pressure-gradient region of a mid-range commercial aircraft swept wing. A segment of the model is designed with a gradually increasing sweep angle and with different airfoil sections along the span to intentionally create strong spanwise gradients, which are neglected in the applied local linear stability theory. Another segment of the model is designed with a constant sweep angle to test a suction panel under conditions comparable to cruise-flight conditions with regard to the calculated instability amplification ratios and to determine the critical N-factor for this suction concept. Initial numerical results of a linear stability calculation employing the method on a RANS calculation of the flow around the model are presented based on different integration paths for the instability amplification ratios.