Solid state current meters

The performance evaluation of several solid-state, no-moving-parts water current meters of different manufacture is reported by the National Oceanographic Instrumentation Center. These tests have uncovered both design deficiencies and operational problems with the instruments. The design of the instruments studied include electromagnetic, vortex-shedding, and acoustic doppler types. In the case of the electromagnetic type, it was found that the principal problems related to the hydrodynamic properties of the transducers and those associated with the electronics and manufacturing. The vortex shedding meter was found to have a lower accuracy, relatively high threshold, and a need for precise alignment to water flow. The greatest problem associated with the doppler meters is reported to be quality of reflected signal. The Center intends to continue its study of no-moving-parts water current meters including those which utilize acoustic and drag force techniques.