A modification of the k-omega shear-stress-transport turbulence model is presented in this paper with the aim to improve the simulation of flows at a low Reynolds number. For this purpose, the incompressible flow at Reynolds number 6 x10^4 , around the Selig–Donovan 7003 airfoil, is investigated by using several turbulence models. The focus is placed on the k-omega shear-stress-transport turbulence model: a model very reliable for transonic flows but for which the application to low-Reynolds-number flows has been questioned. The limits of this model are analyzed in detail. The simulation of the laminar bubble arising on the SD 7003 airfoil has been remarkably improved by the proposed modification. In addition, the accuracy of the k-omega shear-stress-transport turbulence model has been preserved in the transonic regime at a high Reynolds number, as shown by the simulations of the flow around the RAE M2155 wing. Large-eddy simulations of the flow around the Selig–Donovan 7003 airfoil have also been performed and presented in the paper. The large-eddy-simulation data are used as a reference for the results achieved by the Reynolds-averaged Navier–Stokes method. The computed aerodynamic coefficients are compared with some available experimental data

Calculations of the lift and lift-induced drag in steady incompressible high-Reynolds-number flows are proposed in terms of volume integration of the Lamb vector (cross product of the vorticity and the velocity vector). Although conventional far-field methods can compute the profile drag by the volume integral, induced drag is usually obtained by Maskell’s method, which requires a two-dimensional plane cut from three-dimensional data. Using the Lamb vector integration, plane data reconstruction is not necessary, and a definition of the lift-induced drag in viscous flows is obtained. Furthermore, an insight of the drag production is provided by the analysis of the Lamb vector field. Numerical solutions of the flow around arbitrary-shaped bodies can be analyzed by the present method. In particular, the analysis of an elliptic wing is here proposed. The acquired aerodynamic forces are evaluated in comparison with the results of classical methods.

A far-field drag analysis was performed on the computational fluid dynamics simulation results of the NASA Common Research Model produced by Japan Aerospace Exploration Agency for the Drag Prediction Workshop 4. Three levels of grid resolution were employed in that simulation, and the far-field analysis successfully obtained values close to the converged drag values estimated by near-field analysis of the convergence study for all levels of grid. Drag decomposition by the far-field analysis also revealed which parts of the flow and which components of the drag varied with angle of attack. Visualized images of drag production were obtained from the far-field analysis and gave good insight into drag production.