A study on parameters affecting the performance of turbulance amplifiers

Abstract

The turbulance amplifier is one of the two pure digital fluidic elements, and operates on the principle that a laminar jet issuing from a cylindrical tube will remain laminar up to a distance of approximately 100 times the diameter of the tube. If a second tube is placed in the jet path, a part of the laminar flmv can be captured by it, to produce an output pressure, this pressure depending on the average velocity of the jet portion intercepted. If a control tube is placed at right angles to the main jet, disturbances can be introduced into the laminar supply jet by fluid streams of lower energy issuing from the control tube. As a result of this, output pressure will decrease in the output tube. In the work that follows, various parameters, which have pronounced effects on the input-output relations in a turbulance amplifier are considered and in view of dimensional analysis a functional relation between these parameters is obtained. Investigation of jet flow phenomena is based on Schlichting's solution for circular, laminar jets in infinite flow fields; various assumptions and approximations are made to apply this solution to jet flow in a finite field turbulance amplifiers. The analytic study of mixing of jets is based on momentum conservation principle at the point of impinge of control and supply jets. Assumptions and approximations made are verified partially by a series of experiments performed on various models, and partially by experimental data available in literature.