Final Report Summary - VortexCell2050 (Fundamentals of actively controlled flows with trapped vortices)
The 'Fundamentals of actively controlled flows with trapped vortices' (VortexCell2050) project aimed at delivering a new technological platform combining two cutting-edge technologies, the trapped-vortex and the active flow control. Trapping vortices is a technology for preventing vortex shedding and reducing drag in flows past bluff bodies. Active flow control is a form of control which requires energy input. The project outcomes will serve the designers of the next-generation thick-wing aircraft, and will also be applied in other areas where reduction in drag in a flow past a bluff body is desirable.
VortexCell2050 developed a tool for vortex cell design, collected a substantial amount of data on three-dimensional and actively controlled flows in vortex cells, and demonstrated the advantage of a thick airfoil with a properly designed vortex cell with active control over a thick airfoil without a vortex cell, thus opening a possibility of trying this technology in specific applications. VortexCell2050 also highlighted several promising avenues for further improvement of the vortex cell performance. The results of VortexCell2050 ensure European aeronautical sector a leadership in a small but critical area, the importance of which will grow in the future with an increase in aircraft size.
The software tool developed in the project optimises the vortex cell shape for the case of zero mean flow rate of the stabilisation system, as it was initially preconceived, while the developed control scheme requires a non-zero mean flow rate. Therefore, further developments should either generalise the optimisation tool to non-zero mean flow rate or achieve control with zero mean flow rate. The developed scheme of active control should be classified as an open-loop scheme, rather than the initially envisaged closed-loop scheme.
However, the numerical results obtained but not tested in experiment suggest that there are significantly more efficient control schemes. Further work should be concentrated on unsteady and feedback control schemes. The performance of thick airfoil with a vortex cell and control system designed and tested was observed to be better than the performance of the thick airfoil with control system but without the vortex cell, but only in a certain range of the angle of attack, and, more importantly, only when the flow past an airfoil with a vortex cell was in the more favourable branch of the hysteresis loop of the flow regime.
While methods of attaining the favourable branch were identified numerically, further experimental research should take care that the corresponding provisions are made in the design. The results obtained in the project provide a significant step forward as compared to the state of the art. In particular, the development of the software tool for optimising the shape of the vortex cell, the significant body of data on three dimensional effects collected, and the significant body of data obtained on the actively controlled flows past airfoils should be distinguished.
The results of the project were reported at about 40 conferences and in about 20 journal articles. The partners developed close links over the duration of the project, with many parts of the research done in genuine collaboration. As a group, the partners now have a world-leading position in the area of actively controlled flow with trapped vortices.
VortexCell2050 developed a tool for vortex cell design, collected a substantial amount of data on three-dimensional and actively controlled flows in vortex cells, and demonstrated the advantage of a thick airfoil with a properly designed vortex cell with active control over a thick airfoil without a vortex cell, thus opening a possibility of trying this technology in specific applications. VortexCell2050 also highlighted several promising avenues for further improvement of the vortex cell performance. The results of VortexCell2050 ensure European aeronautical sector a leadership in a small but critical area, the importance of which will grow in the future with an increase in aircraft size.
The software tool developed in the project optimises the vortex cell shape for the case of zero mean flow rate of the stabilisation system, as it was initially preconceived, while the developed control scheme requires a non-zero mean flow rate. Therefore, further developments should either generalise the optimisation tool to non-zero mean flow rate or achieve control with zero mean flow rate. The developed scheme of active control should be classified as an open-loop scheme, rather than the initially envisaged closed-loop scheme.
However, the numerical results obtained but not tested in experiment suggest that there are significantly more efficient control schemes. Further work should be concentrated on unsteady and feedback control schemes. The performance of thick airfoil with a vortex cell and control system designed and tested was observed to be better than the performance of the thick airfoil with control system but without the vortex cell, but only in a certain range of the angle of attack, and, more importantly, only when the flow past an airfoil with a vortex cell was in the more favourable branch of the hysteresis loop of the flow regime.
While methods of attaining the favourable branch were identified numerically, further experimental research should take care that the corresponding provisions are made in the design. The results obtained in the project provide a significant step forward as compared to the state of the art. In particular, the development of the software tool for optimising the shape of the vortex cell, the significant body of data on three dimensional effects collected, and the significant body of data obtained on the actively controlled flows past airfoils should be distinguished.
The results of the project were reported at about 40 conferences and in about 20 journal articles. The partners developed close links over the duration of the project, with many parts of the research done in genuine collaboration. As a group, the partners now have a world-leading position in the area of actively controlled flow with trapped vortices.
