Numerical Study of Turbulent Air and Water Flows in a Nozzle Based on the Coanda Effect

Abstract

In the present work it is performed a numerical study for simulation of turbulent air and water flows in a nozzle based on the Coanda effect named H.O.M.E.R. (High-Speed Orienting Momentum with Enhanced Reversibility). The main purposes of this work are the development of a numerical model for simulation of the main operational principle of the H.O.M.E.R. nozzle, verify the occurrence of the physical principle in a device using water as working fluid and generate theoretical recommendations about the influence of the difference of mass flow rate in two inlets and length of septum over the fluid dynamic behavior of water flow. The time-averaged conservation equations of mass and momentum are solved with the Finite Volume Method (FVM) and turbulence closure is tackled with the k-ε model. Results for air flow show a good agreement with previous predictions in the literature. Moreover, it is also noticed that this main operational principle is promising for future applications in maneuverability and propulsion systems in marine applications. Results obtained here also show that water jets present higher deflection angles when compared with air jets, enhancing the capability of impose forces to achieve better maneuverability. Moreover, results indicated that the imposition of different mass flow rates in both inlets of the device, as well as central septum insertion have a strong influence over deflection angle of turbulent jet flow and velocity fields, indicating that these parameters can be important for maneuverability in marine applications.

Induced Circulation by Plunging and Submerged Jets in Circular Water Storage Tanks Using CFD

“…This phenomenon is known as the 'Coanda effect', which is the tendency of a stream to stay attached to a convex surface. This attachment pulls in the flow, adding a horizontal velocity component in the wall direction [47,48].…”

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

“…Coanda effect is the adhesion of a high speed jet to a convex surface. Coanda effect is essentially utilized in aerospace applications [5], heating/cooling [6] and marine technology [7]. There are three alternative nozzle configurations for the utilization of Coanda surfaces: Newman setup [4] with only one jet next to the convex surface, Juvet setup [8] with two primary jets and a control jet and HOMER nozzle setup [1] composed of two inlets, two Coanda surfaces, one pintle to separate and smoothly direct these jets and a converging-diverging nozzle to enclose whole components.…”