Numerical investigation on Coanda flow over a logarithmic surface

The Coanda effect has been introduced into lift generation designs. In this paper, a logarithmic spiral surface is introduced as a curvature shape to evaluate the development of jet flow along the Coanda curvature. Moreover, 2D computational fluid dynamics numerical simulation is adopted to measure velocity profile, jet width growth, maximum velocity decay, and surface static pressure along the curvature surface. A parametric study on the effect of varying exit jet heights on the Coanda effect is also presented. Results show that jet width grows proportionally along the curved surface, and the proportional decay of maximum velocity and surface pressure is lower than the atmospheric pressure. A wider exit jet height produces lower static pressure on the unmanned aerial vehicle surface and a slower maximum velocity decay. Overall parametric analysis of varying exit jet heights shows that the effective range of d/R is 0.1 to 0.14.