Abstract: The preliminary numerical method and wind tunnel test research were conducted based on the modified natural laminar flow wing cover configuration of a business jet flight test platform, with the flight test as the core. Both wind tunnel tests and flight tests use the infrared (IR) thermal imaging technology for transition detection. Meanwhile, the LST-based e^N method is used to carry out numerical simulation analysis of the experimental configuration, and to explore the influence mechanism of the angle of attack and pressure distribution on the dominant transition of Tollmien-Schlichting (T-S) wave instability. The research results show that the wind tunnel test configuration maintains a wide range of favorable pressure gradients on the upper surface in the angle of attack range of -2°-2°, and the T-S wave growth is effectively suppressed, achieving a chord length of more than 50% of the laminar flow region. In the laminar flow region, transition occurs in the pressure recovery area. An obvious inverse pressure gradient appears close to the leading edge at 4°, the T-S wave grows rapidly, and the transition position moves up to 20%c. The results under the flight test conditions show that the influence mechanism of the pressure distribution on the T-S wave is consistent with that in the wind tunnel test. Under the high turbulence and low Reynolds number wind tunnel test conditions, and the low turbulence and high Reynolds number flight test conditions, we use turbulence intensity and Mack formula to determine the critical N factor of the T-S wave, and the obtained transition prediction results are in good agreement with the experimental results, indicating that the numerical method has good prediction accuracy and robustness.

Key words: natural laminar flow, wing glove, transition prediction, e^N method, wind tunnel test, flight test