Prediction of Laminar Separation Bubble on Airfoils at Low Reynolds Number

Abstract The accurate prediction of Laminar Separation Bubbles (LSBs) is crucial for understanding transition mechanisms and aerodynamic performance of airfoils operating at low Reynolds numbers. This study employs the Linearized and Segregated Variational Multiscale (VMS) Method to simulate LSB formation and development on airfoils. The methodology is validated against two well-documented test cases: SD7003 airfoil $${\boldsymbol{Re}}=60\,000$$ , $$\boldsymbol{AoA}={4}^{\circ}$$ and the E387 airfoil at $${\boldsymbol{Re}}=3\times 10^{5}$$ , $$\boldsymbol{AoA}=1^{\circ}$$ . The results demonstrate strong agreement with reference data from the literature, accurately capturing pressure and skin friction distributions as well as velocity profiles associated with LSB dynamics. To further assess the method’s predictive capability, simulations are performed on a DU89-134 airfoil, designed for High Altitude Pseudo Satellites (HAPS) applications at $${\boldsymbol{Re}}=5\times 10^5$$ , $$\boldsymbol{AoA}=1^{\circ}$$ , 5 ∘ . Comparisons with experimental vertical velocity profiles - obtained with hot-wires anemometry - show excellent agreement, confirming the method’s robustness in transitional flow modelling. These findings highlight the effectiveness of the Linearized and Segregated VMS approach for Large Eddy Simulations of LSBs. The method provides a reliable tool for aerodynamic analysis of low-Reynolds-number airfoils, with potential applications in next-generation high-altitude flight vehicles.