Stereo PIV study of flow around a live swimming fish
Sakakibara, J., Nakagawa, M., Yoshida, M., 2004, "Stereo-PIV study of flow around a maneuvering fish", Experiments in Fluids, Vol.36, pp.282-293. (PDF)
Flow around a live fish in turning motion has been experimentally
investigated using stereo-PIV. A gold fish, 90mm in length, was released in a rectangular
Plexiglas tank (200mm x 800mm) in horizontal cross-section,
200mm depth of water) with tracer particles ( 50 micron in diameter),
and a laser light sheet illuminating vertical (horizontal)
plane visualized a flow behind (around) the fish. Two of CCD cameras
captured the particle images, and the other two of CCD cameras
captured the fish's body to reconstruct quasi 3D volumetric shape of the fish.
The fish, in turning motion, bends its body quickly to change
the direction of the head, and then sweeps the tail. Two jets were formed near
the tail; one is perpendicular to the body axis which produces thrust to rotate
the body, and the other is for backward to swim straight forward after the
turn. The vertical slice of the velocity field shows those jets
having approximately same length scale as height of the tail.
Click to see animation
Three-components velocity in a vertical plane
behind a fish in turning motion measured by stereo-PIV;
vectors:in-plane, color contours:out of plane component.
Three-dimensional fish shape, represented by green surface,
was measured at same time.
Click to see animation
Three-components velocity in a horizontal plane
around a fish in turning motion measured by stereo-PIV;
vectors:in-plane, color contours:out of plane component.
Three-dimensional fish shape, represented by green surface,
was measured at same time.
Click to see animation
Three-components velocity in a horizontal plane
around a fish in rising motion measured by stereo-PIV;
vectors:in-plane, color contours:out of plane component.
Three-dimensional fish shape, represented by green surface,
was measured at same time.
Click to see animation
Two-dimensional velocity around a fish in turning motion
measured by PIV.
Schematic of three-component velocity and shape measurement
around a fish. CCD1 and CCD2 capture PIV images in the light sheet plane.
CCD3 and CCD4 capture the shadows of the fish, then common volume
of those projections are identified as the fish body.
A snap shot of an experiments on measureing
flow behind a fish by stereo-PIV