A comparative numerical study of the coanda effect

The tendency of a fluid or a gas jet to stay attached to a convex surface, named as Coandg effect, after the Romanian scientist Henri Marie Coandg who is considered the first to have investigated it, has many practical applications. The approaching jet adheres along the whole as long as the surface is not too sharply curved. The adherence is due to the developing, along the liquid interface, of pressures lower than the external pressure. In this paper pressure distributions caused by a 2D water jet on convex surfaces is numerically investigated. Steady flow characteristics are deduced by means of three different solvers: a pure Lagrangian, based on the Weakly Compressible Smoothed Particle hydrodynamics (WCSPH) technique, COMSOL Multiphysics and Flow-3D. For sake of clarity, elliptic shaped solid contours are taken into account. Results, consisting of pressure profiles and dynamic thrust, are investigated in terms of the ratio R1/R2 being R1 and R2 the major and minor radius respectively.