Measurement of the slope of a liquid free surface along a line by a schlieren system with anamorphic elements

THOMAS, LP; GRATTON, R; MARINO, BM; BETELU, S; DIEZ, JA; SIMON, J.

MEASUREMENT SCIENCE & TECHNOLOGY (PRINT)

IOP Publishing Limited

Año: 1996 vol. 7 p. 1134 - 1139

0957-0233

We describe and test a simple quantitative schlieren method for measuring the slope of an unsteady free liquid surface along a straight segment. The optical system, based on an anamorphic element placed at the focal plane of a standard objective, forms a distorted image of the illuminated segment on a screen. The abscissa of the resulting bright curve is proportional to the coordinate along the segment and the ordinate to the longitudinal slope at the corresponding coordinate, provided that the transverse slope component is negligible. The method is useful to probe axisymmetric flows along a diameter or flows in straight channels along the axis.