FIBEROPTIC SPATIAL FILTER VELOCIMETER FOR MEASUREMENT OF LOCAL LIQUIDVELOCITY

The spatial filtering velocimetry is the basis of the new optical hydr ometric measuring probe. like a laser Doppler velocimeter, the hydrome tric probe determines the velocity of tracer particles in the liquid f low. Essential parts of the hydrometric probe are a differential fibre optical spatial filter and an illumination source. The tracer particle s are imaged onto the spatial filter by a shadow projection with a par allel light beam. The hydrometric probe can be used for velocity and f low measurements in pipes and river flows. The technique permits the d esign of robust and low cost optical hydrometric probe which can be us ed for different hydrometric applications. (C) 1997 Elsevier Science L td.