Switching Control of Latex Balloon Expansion by using Switching Valve mediated with the Coanda Effect

Soft robots have advantages in terms of safety, softness, and compliance compared to traditional robotic systems. However, fluid-driven soft actuators, often employed in soft robots, require a corresponding number of bulky pressure supplies/valves to drive. Here, we consider a valve that can control the flow without mechanical moving parts for simplifying the driving system of soft actuators. We developed a system comprising a pump, a switching valve, and two latex balloons to demonstrate the feasibility of introducing a fluid valve into soft robotics. As the valve, which makes use of the Coanda effect, can switch the flow between two outlets when the pressure difference between the outlets is 3 kPa, we employed a latex balloon connected to each outlet. The system can control the expansion of each balloon by switching the flow from the pump. The experimental results proved that the system could actuate each balloon.

Reduced dust generation when loading hoppers with powdered material. Part 2. Results of numerical-experimental studies

On the basis of the obtained analytical dependencies, the expediency of fan loading of bunkers with powdery bulk material has been proved. The design of an annular charging device, which reduces dust formation, using the Coanda effect is proposed. The rational design and technological parameters of the developed device are numerically and experimentally determined.

Pressure Distribution On A Flat Plate In The Context of The Phenomenon of The Coanda Effect Hysteresis

As a result of the Coanda effect, a symmetrical free jet will flow as an asymmetrical wall jet. At the same time, at the obstacle along which the flow is observed, the wall jet generates pressure distribution. In this study, the obstacle located at the diffuser outlet is a flat plate with a variable inclination angle. The article presents results of the study on pressure distributions on a flat plate with a variable angle of inclination. What is new, however, is that the presented results of the experimental research include the influence of the Coanda effect hysteresis on the pressure distribution on the plate. The article shows how pressure distributions change on the plate depending on whether the initial angle of inclination was 0 degree and was increased gradually in the course of the experiment until a detachment of the jet flowing from the plate was observed, or the initial angle of inclination was close to 90 degrees in the primal state and as the angle of the plate inclination was decreased, the jet flowing towards the plate reached the state of attachment to the plate surface.

Experimental and Numerical Study on the Performance Change of a Simple Propeller Shape Using the Coanda Effect

In this study, a jet injection propeller was designed to increase its efficiency, and the results were compared by open water tests and numerical computations. Also, the change in shape of the slit and injection volume conditions, which are difficult to perform experiments with, were analyzed through computations. The jet injected from the blade surface generates additional thrust due to the Coanda effect, and the jet injection generates a moment in the direction of propeller rotation, resulting in a decrease in the total torque. Computations were performed for three slit heights. When the height of the slit is high, the efficiency of the propeller increases, even if the power of the pump required for jet injection is considered. The result was found to increase the efficiency by about 8.7%, even when the efficiency was compared under the condition of generating the same thrust by controlling the injection volume of the jet by designing a normal propeller that does not inject a jet.