USA As Represented by Secretary of the Navy

Paul J Lefebvre

William P Barker

John A Schwemin

William W Durgin

The present invention relates to measuring device for measuring a component f a force acting on a test body, such as a hydrofoil, positioned within a testing apparatus. The measuring device has a test body formed by a foil shaped center section and two adjacent end sections. Each end section is joined to the center section by a flexure member having sufficient stiffness so that there is negligible relative motion between the center section and the end sections as a fluid medium flows past the center section. At least one strain gauge is mounted to at least one flexure member to measure the forces acting on the center section. A method for measuring the load on a test body is also described.

Hydrofoil force balance

A system is described for providing means by which the flow in a fluid such s water in a fluid flow loop can be accurately controlled to undergo user defined transients. Besides, the system allows for velocity variations over a wide range of velocities.

Transient flow loop system

An electromagnetic flowmeter and a method for measurement of the rate of flow of a fluid under unsteady conditions are described. It uses fluid steady-state flowmeter technology and a new algorithm to measure transient rate of flow of a fluid such as water. The algorithm teaches (a) measuring the e.m.f. generated due to the rate of flow of the fluid under test moving through a tube placed in an area with uniform magnetic flux, and (b) comparing it to a simultaneously generated reference signal which is measure of the magnetic flux density generated when an electromagnetic flowmeter is energized due to the fluid flow rate at the instant of taking the flow rate data of the fluid.

Method and flowmeter for unsteady fluid flow study

An apparatus for defining the free surface of a moving column of a fluid in vertical pipe to enhance the accuracy of measurements of transient rate of flow of the fluid using electromagnetic flowmeter is described. It provides a neutrally buoyant plug which stays in contact with the free surface of the column of the fluid at all times and thus defines the free surface of the fluid moving in the vertical pipe accurately and reduces the oscillations of the free surface of the fluid.

Transient flowmeter calibration facility

A facility for permitting launch performance tests to be conducted on an erwater vehicle, such as a torpedo, includes a housing having an opening therethrough defining a tubular chamber for receiving a vehicle therein. A piston is also positioned within the tubular chamber. A link disposed between the piston and the vehicle has a pair of opposing end portions connected with the piston and the vehicle, respectively. A channel is positioned adjacent to the housing and has water flowing therein at a predetermined velocity. The water within the channel communicates with the tubular chamber to allow water flowing within the channel to enter the tubular chamber and surround the vehicle with the vehicle at its rest position. A drive device is operable to move the piston through the tubular chamber a preselected distance sufficient to move the vehicle and the water surrounding the vehicle out of the tubular chamber and into the channel. The link is connected with the piston and the vehicle to permit the vehicle to move both laterally and in rotational fashion within the tubular chamber with the vehicle at its rest position and as the vehicle moves through the tubular chamber in response to hydrodynamic forces acting on the vehicle generated by the flowing channel water and also to stop the advancement of the vehicle after the piston has moved its preselected distance.

Underwater vehicle launch performance test facility

A system is described for testing a pump or a turbine impeller under transient operating conditions in a fluid flow. The system provides simultaneously, as a function of time, user defined impeller speeds, fluid flow rate and rise in fluid pressure so as to simulate real conditions. This information can be used to analyze the performance of existing impellers or for designating new impellers.

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Tiverton, RI, United States of America

Paul J Lefebvre