Experimental investigation and numerical verification of Coanda effect on curved surfaces using co-flow thrust vectoring

Abstract

In this study, a popular co-flow thrust vectoring system, which is superior to typical Coanda nozzles with one main jet, is examined experimentally and compared with 2D and 3D computational fluid dynamics results. High Speed Orienting Momentum with Enhanced Reversibility nozzle concept is the base design to proposed configuration which uses a control jet additional to the main jet for better and active enhancement on the flow vectoring and streamlined side-walls resulted in less flow blockage. This comparatively novel concept is utilized in an experimental setup to direct the thrust of aerial vehicles. The system includes two inlets (inlet1, inlet2) with different jet velocities and one pintle to separate and smoothly direct these jets and a converging-diverging nozzle to enclose these components. Experimental study is accomplished with four different configurations of inlet1 and inlet2 as 15 m/s and 10 m/s; 20 m/s and 10 m/s; 30 m/s and 10 m/s, and 45 m/s and 10 m/s, respectively. The tangential velocities on the curved surfaces are successfully measured utilizing a micro-manometer (Pitot tube) so that attachments/detachments of jets on the exit walls and deflection angles are calculated for each inlet velocities. The current experimental study also revealed that 3D assumption of computational fluid dynamics of Coanda effect is highly accurate and deflection angle results are not far from experimental results with the average deficit of only 5.44 %. As the result, 3D verification study resembles to experimental study in terms of deflection angles for all configurations.