Performance, applicability and limitations of the Baldwin-Lomax model
The Baldwin-Lomax model is suitable for high-speed flows with thin attached boundary layers. Typical applications are aerospace and turbomachinery applications. It is a low-Re model and as such it requires a fairly well-resolved grid near the walls, with the first cell located at 1. The model is popular in quick design-iterations due to its robustness and reliability. It seldom leads to any convergence problems and it seldom gives completely unphysical results. The computation of most of the model looks to relatively straightforward. The model is nonlocal in nature due to the presence of the damping function. This means that for any location in the flow interior, we need a wall (or other suitable location) to compute a from. Further, the calculation of and is better suited to a structured grid in which grid lines emanate outward from a wall (or wakeline, etc.). The determination of and is sensitive to gridpoint location, as the vorticity magnitude is typically only available pointwise. Finally, it is tempting to use the minimum of the two (inner and outer) eddy viscosity results (as well in our case) instead of the correct crossover formula. This simplifies the programming, but is not justifiable on any other grounds (and can lead to the use of the wrong eddy viscosity). The (minimal) additional programming is required for correct implementation of this model.