Search

This paper presents an optimization framework based on an open-source CAD system and CFD solver. In this work, the high-fidelity flow solutions and surface sensitivities are obtained using the primal and discrete adjoint formulations of $SU^2$. This paper shows the direct use of CAD models for optimization by developing a CAD system application programming interface, and creating a link between CAD-MESH-CFD analysis. A methodology to obtain geometric sensitivities is introduced, enabling the calculation of accurate gradients with respect to CAD variables and the deformation of the analysis mesh during the optimization process. This methodology guarantees that the new surface mesh lies exactly on the computer-aided-design geometry. The optimization framework is applied to a rectangular wing and a three section high-lift aerofoil configuration derived from the NASA CRM-HL configuration. Both geometries are created using FreeCAD. The performance objectives are to decreased drag while constraining the lift to be above a desired value. The twist distribution of the wing was parameterized within the CAD system, allowing the minimization of the induced drag by obtaining a nearly elliptical lift distribution. For the high-lift configuration, the position and rotation of the flap and slat were parameterized with respect to the original section; the final optimised positions yield a drag reduction of approximately 16.5\%. These results show that the CAD parameterization can be reliably used to obtain efficient optimums, while operating directly on the CAD geometries.

Background and Aims: The resurgence of malaria, particularly in the developing world, is considerable and exacerbated by the development of single-gene multi-drug resistances to chemicals such as chloroquinone. Drug therapies, as recommended by the World Health Organization, now include the use of antimalarial compounds derived from Artemisia annua – in particular, the use of artemisinin-based ingredients. Despite our limited knowledge of its mode of action or biosynthesis there is a need to secure a supply and enhance yields of artemisinin. The present study aims to determine how plant biomass can be enhanced while maximizing artemisinin concentration by understanding the plant's nutritional requirements for nitrogen and potassium. Methods: Experiments were carried out, the first with differing concentrations of nitrogen, at 6, 31, 56, 106, 206 or 306 mg L–1 being applied, while the other differing in potassium concentration (51, 153 or 301 mg L–1). Nutrients were supplied in irrigation water to plants in pots and after a growth period biomass production and leaf artemisinin concentration were measured. These data were used to determine optimal nutrient requirements for artemisinin yield. Key Results: Nitrogen nutrition enhanced plant nitrogen concentration and biomass production successively up to 106 mg N L–1 for biomass and 206 mg N L–1 for leaf nitrogen; further increases in nitrogen had no influence. Artemisinin concentration in dried leaf material, measured by HPLC mass spectroscopy, was maximal at a nitrogen application of 106 mg L–1, but declined at higher concentrations. Increasing potassium application from 51 to 153 mg L–1 increased total plant biomass, but not at higher applications. Potassium application enhanced leaf potassium concentration, but there was no effect on leaf artemisinin concentration or leaf artemisinin yield. Conclusions: Artemisinin concentration declined beyond an optimal point with increasing plant nitrogen concentration. Maximization of artemisinin yield (amount per plant) requires optimization of plant biomass via control of nitrogen nutrition.