The purpose of this work is to verify the theoretical analysis obtained by the authors on the propagation of harmonic pressure waves through viscous compressible fluids contained in flexible viscoelastic tubes. A system consisting of hydraulic oil and nylon tubes was used as a hydraulic transmission line. Two nylon tubes of different materials were used in this experimental study. The phase velocity and the damping constant of the pressure waves were measured to determine the viscoelastic model of the tube material. The peripheral strain at a certain point on the tube was measured to verify the viscoelastic model and to clarify the relationship between the fluid pressure and tube radial motion. The frequency response tests of hydraulic transmission lines were carried out and good agreement between experimental and theoretical results was obtained. It is concluded on the basis of the experimental evidence that this theory can describe the dynamic behavior of liquid lines contained in viscoelastic tubes.

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An oriffice type flow measuring system needs a square root converter for integration, the output of which is proportional to the flow.
This work deals with a new converter which extracts the square root of the pneumatic inpuf pressure (0.2-1.0kgf/cm²) from a differential pressure transmitter and converts it into angular velocity. The pneumatic square root converter is realized here by the use of the gyro-moment. The square root extraction is made by a high gain pneumatic amplifier and a feedback-element with a square character using the gyro-moment.
This paper describes theoretical and experimental works on static and dynamic characteristics of the converter. Experiments show that the converter has an sufficient accuracy for industrial uses. Furthermore some problems to be solved for better performance are discussed.

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