Thin-film gauges for the measurement of velocity or skin friction in air, water or blood.

Abstract

The design, manufacture and calibration of a range of thin-film, heated-element gauges to measure instantaneous velocity or skin-friction in air, water or blood is described. The probes consist of a platinum resistance thermometer which is heated electrically, with additional elements to detect reversed flow. The manufacturing technique of a flush-mounted skin-friction gauge, and a needle probe currently used in the diagnosis of heart conditions in man, is described in detail.