Computational Fluid Dynamics Analysis and Optimization of the Coanda Unmanned Aerial Vehicle Platform

It is known that using Coanda aerosurfaces can drastically augment the lift forces when applied to an Unmanned Aerial Vehicle (UAV) platform. However, Coanda saucer UAVs, which commonly use a dish-like, radially-extending structure, have shown no significant increases in thrust/lift force and therefore have never been commercially successful: the additional thrust/lift generated by the Coanda surface diminishes since the airstreams emerging from the rotor compartment expand radially causing serious loss of momentums and therefore a net loss of total thrust/lift. To overcome this technical weakness, we propose to examine a Coanda surface of straight, cylindrical design and optimize its geometry for highest thrust/lift utilizing computational fluid dynamics software ANSYS Fluent®. The results of this study reveal that a Coanda UAV configured with 4 sides of straight, cylindrical Coanda surface achieve an overall 45% increase in lift compared to conventional Coanda Saucer UAV configurations. This venture integrates with an ongoing research project where a Coanda prototype is being assembled. Additionally, a custom thrust-stand has been constructed for thrust/lift measurement.

• Nigel Q. Kelly
• Zaid Siddiqi
• Jin W. Lee

• CFD
• Coanda
• Lift
• UAV.

[1] P. M. Gerhart, A. L. Gerhart, and J. I. Hochstein, Fundamentals of Fluid Mechanics, 8th Edition. 2016.
[2] A. Akturk and C. Camci, “Tip Clearance Investigation of a Ducted Fan used in VTOL UAVs PART 1 : Baseline Experiments and Compuational Validation,” 2011.
[3] B. T. Fraser et al., “Review on Progress and Application of Active Flow Control Devices - Coandă Effect on Unmanned Aerial Vehicles,” Retrieved Oct., vol. 3, no. 1, pp. 113–137, 2018, doi: 10.4995/var.2015.4366.
[4] H. Coanda, “Propelling Device,” 2,108,652, 1938.
[5] F. Nedelcut, “Towards a new class of aerial vehicles using the coanda effect,” Univ. Galati, 2008.
[6] O. Crivoi, I. Doroftei, and F. Adascalitei, “A Survey on Unmanned Aerial Vehicles Based on Coanda Effect,” Tehnomus, no. 20, pp. 338–344, 2013.
[7] H. Djojodihardjo, R. I. Ahmed, and A. Yousefian, “An analysis on the lift generation for Coandə micro air vehicles,” Proceeding - ICARES 2014 2014 IEEE Int. Conf. Aerosp. Electron. Remote Sens. Technol., pp. 164–169, 2014, doi: 10.1109/ICARES.2014.7024387.
[8] R. I. Ahmed, A. R. Abu Talib, A. S. M. Rafie, and H. Djojodihardjo, “Aerodynamics and flight mechanics of MAV based on Coandă effect,” Aerosp. Sci. Technol., vol. 62, pp. 136–147, 2017, doi: 10.1016/j.ast.2016.11.023.
[9] N. Mirkov and B. Rasuo, “Maneuverability of an UAV with COANDA effect based lift production,” 28th Congr. Int. Counc. Aeronaut. Sci. 2012, ICAS 2012, vol. 3, pp. 1745–1750, 2012.
[10] N. Mirkov and B. Rašuo, “Numerical simulation of air jet attachment to Convex walls and application to UAV,” Lect. Notes Comput. Sci. Eng., vol. 108, pp. 197–207, 2015, doi: 10.1007/978-3-319-25727-3_15.
[11] “The GFS UAV Project, A coanda effect flying saucer tested by Jean-Louis Naudin.” http://jlnlabs.online.fr/gfsuav/index.htm (accessed Jul. 26, 2020).
[12] C. D. Argyropoulos and N. C. Markatos, “Recent advances on the numerical modelling of turbulent flows,” Appl. Math. Model., vol. 39, no. 2, pp. 693–732, 2015, doi: 10.1016/j.apm.2014.07.001.
[13] V. Dragan, “A new mathematical model for high thickness coanda effect wall jets,” Rev. Air Force Acad., vol. 1, no. 1, pp. 23–28, 2013.