Large-Field and Focusing Schlieren Methods

Abstract

Schardin essentially overlooked the large-scale possibilities of the lens-and-grid schlieren technique which he and H. Maecker pioneered [2]. Sixty years later, this and other opportunities have emerged to free the schlieren technique from its traditional bonds of small scale. Concurrently some of these approaches allow narrow depth-of-field as well, hence the ability to focus upon a “plane” in a 3-D schlieren field. Both possibilities are crucial to the renewed vitality of schlieren imaging.

In most cases it is unfortunately impossible to study thermo-hydrodynamic flowfields at full scale, owing to the limited dimensions of the available mirrors.

Hubert Schardin [1]