Flow Measurement with a Suspension Wire

A flow measuring device based on the drag developed on a wire suspend transverse to the flow of water has been developed. The wire is suspended between a fixed support and an elastic support, with the wire deflection registered by a semiconductor strain gage incorporated at the elastic end. The gage formed part of a Wheatstone bridge circuit with a sensitive galvanometer and d-c amplifier recorder. The basic operating principle was studied in series of tests with the wire completely traversing a 2 in. diameter closed conduit and then the 11 in. dimension of a 11 in. by 5-1/2 in. closed circuit water tunnel, together with wire types varying from 0.001 in. to 0.0071 in. in diameter of different materials. A probe with a wire length of the order of 1 in. extended the work for open-channel flows. Velocity distributions have been determined within a wire diameter of the channel floor. The dynamic response of the probe in the vortex wake of a fixed cylinder and stability in sediment load also were investigated.