Laminar-turbulent transition delay on a swept wing

摘要: The paper describes the results of experiments on robustness laminar-turbulent transition control a swept-wing using distributed micro-sized roughness (DMSR) elements. These elements introduce controlled stationary vortices which are able to significantly modify base flow and its stability characteristics. We have performed parametric study first varying height period DMSR in order find most stabilizing effect boundary later compare uncontrolled reference case without DMSR. Significant downstream shift position due application is found well documented with help thermography. this method was studied by variation wind-tunnel quality introducing significant sound background or enhanced turbulence level (applying turbulizing grids). tests turbulence-generating grids (at levels) shown that moves upstream case, while DMSR-elements loose their effectiveness for (no matter quiet conditions at elevated background). acoustic influence does not location. However, then delayed presence DMSR, an additional delay observed when harmonic waves certain frequency were excited.The laminar-turb...