Kunihiro Ogihara

An Application of the Moiré Fringe Method: Measurement of the Motion of a Submerged Body

ABSTRACTThe dominant direction of the motion of a submerged body does not always coincide with the direction of the wave propagation, and under such circumstances it requires expensive and troublesome techniques to determine the movement of the body even in laboratory. The present paper gives a simple method for this purpose which needs only one photograph to calculate the three dimensional positions of a marked point on the body, based upon the principle of the moire-fringe photograph.Colored stripes projected on the body through the slide projector are used in the experiments. An example is given in detail. The authors conclude that the method gives results with sufficient accuracy and at the same time the method provides the cheapest way for experiment.