Prediction of a Laminar Separation Bubble on low-Reynolds Airfoils using Variational Multiscale Method

The paper presents the application of a finite element numerical approach for predicting the development and locating the Laminar Separation Bubble (LSB) on low Reynolds airfoils. The method is a linearized and segregated variation of the Variational Multi-Scale method (LS-VMS). The aim is to demonstrate the validity of this new method, overcoming the need for calibration based on experiments and/or custom-fitting transition functions. It has been tested on the SD7003 airfoil at Re = 60 000, obtaining results aligned with previously published experimental and numerical results. Furthermore, it has been tested for the DU89-134 profile, a high lift-to-drag ratio airfoil used for high-altitude pseudo-satellite applications. For this geometry, various configurations (AoA = 5^◦, Re = 250 000, 500 000) compatible with low stratospheric flight have been examined and compared with RANS simulations using the γ - Re_θ transitional model showing close agreement.