The paper describes the results of experiments on robustness of laminar-turbulent transition control on a swept-wing using distributed micro-sized roughness (DMSR) elements. These elements introduce controlled stationary vortices which are able to significantly modify the base flow and its stability characteristics. We have performed parametric study first varying height and period of the DMSR elements in order to find the most stabilizing effect on boundary later flow in compare to uncontrolled reference case without DMSR. Significant downstream shift of laminar-turbulent transition position due to application of DMSR is found and well documented with help of thermography. The robustness of this flow control method was studied by variation of the wind-tunnel flow quality introducing significant sound background or introducing enhanced turbulence level (applying turbulizing grids). The wind-tunnel tests performed with turbulence-generating grids (at enhanced turbulence levels) have shown that laminar-turbulent transition moves upstream in this case, while DMSR-elements loose their effectiveness for transition control (no matter in quiet sound conditions or at elevated sound background). The experiments on acoustic influence have shown that without DMSR acoustic does not effect transition location. However, in case then laminar-turbulent transition is delayed by presence of DMSR, an additional transition delay was observed when harmonic acoustic waves of certain frequency were excited.
Laminar-turbulent transition delay on a swept wing
INTERNATIONAL CONFERENCE ON THE METHODS OF AEROPHYSICAL RESEARCH (ICMAR 2016): Proceedings of the 18th International Conference on the Methods of Aerophysical Research ; 2016 ; Perm, Russia
AIP Conference Proceedings ; 1770 , 1
2016-10-13
12 pages
Conference paper
Electronic Resource
English
Large-Eddy Simulation of Laminar-Turbulent Transition in a Swept-Wing Boundary Layer
British Library Conference Proceedings | 1997
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