The present invention relates to a method for measuring the velocity of a flow field using visualization techniques, and the velocity value changes by varying the length of the trajectory according to the threshold holding value set by the measurer, thereby making it difficult to accurately measure the velocity. In particular, to solve the conventional problem that the acceleration value can not be obtained at all.;In order to solve this problem, the present invention floats fine particles in a flow field and sends a sheet laser to the screen to contain the particle flow on the sheet surface, reducing the error (error) due to the slash holding when analyzing the trajectories on the particles. Not only can the value be obtained, but also the acceleration value can be obtained.
展开▼