Abstract

This paper describes a method of eliminating the directional ambiguity in the flow velocity measured in a microscopic region using a transmission grating. The opposite directions of the flow are discriminated from the phase relation between two output signals obtained from the two photodetectors with transmission gratings. The method is applied to measurements of flow velocity in a small (3-mm diam) glass tube. The experimental results verify the usefulness of the method for determining the flow direction in transmission grating velocimetry.

© 1985 Optical Society of America

Measurements of flow velocity in a microscopic region using a transmission grating: a differential type

Yoshihisa Aizu, Tsuyoshi Ushizaka, and Toshimitsu Asakura
Appl. Opt. 24(5) 627-635 (1985)

Measurements of flow velocity in a microscopic region using a transmission grating

Tsuyoshi Ushizaka and Toshimitsu Asakura
Appl. Opt. 22(12) 1870-1874 (1983)

Measurements of the velocity gradient in a microscopic region using a transmission grating

Yoshihisa Aizu, Tsuyoshi Ushizaka, and Toshimitsu Asakura
Appl. Opt. 24(5) 641-647 (1985)

Measurements of flow velocity in a microscopic region using a transmission grating: a practical velocimeter

Yoshihisa Aizu, Tsuyoshi Ushizaka, Toshimitsu Asakura, and Tomiyasu Koyama
Appl. Opt. 25(1) 31-38 (1986)

Removal of Pedestals and Directional Ambiguity of Optical Anemometer Signals

F. Durst and M. Zaré
Appl. Opt. 13(11) 2562-2579 (1974)