Hydrodynamics and structure of free liquid surfaces

The reflectance Schlieren technique has been successfully adapted to the measurement of the shapes of free moving liquid surfaces over a wide range of flow conditions, The measurements are sufficiently detailed and accurate to describe the underlying fluid motion when an adequate hydrodynamic model is available. Furthermore this information could then be successfully used to predict interfacial transport rates of dissolved gases, for example, oxygenation. Measurements of surface shape were made on turbulent open channel flows and also on surface tension driven Benard cells. These measurements cover a range of 0.65 mm to .00015 mm vertical surface deflections induced by the fluid motion underneath.