Measurement of low frequency current from a fixed platform

Currents measured from large fixed platforms have errors caused by flow interference from the platform members. Such errors are studied by analyzing measurements made at the Ocean Test Structure (OTS) where current meters were mounted on all four corner legs of the platform, each oriented radially outward from the platform. The measurement errors are found to be dominated by flow interference. The errors have a consistent relation to the relative angle of attack of the steady flow, are approximately linearly proportional to the steady flow speed and are roughly doubled by marine growth on the structure. Because the errors are consistent, the measurements are repeatable and therefore platforms are useful vehicles for current measurement.