The X Displacement and Y Displacement variables determine the distance the particles travel from the first image to the second image. As discussed in Region Size, the PIV correlations are most likely to remain valid if the total translation of the particles from the first to second image are within ΒΌ of the interrogation region size. This result is due to the number of particles which are gained/lost due to too large of particle translations. However, while limiting the particle translations to very low will result in a larger number of valid correlations, the maximum range of velocities described by the PIV results would also be low. As with many other PIV parameters, this balance results in a trade-off between maximizing the particle displacements from the first to second images while retaining enough particles in the interrogation region to result in valid correlations.
Author: Jack Elliott
Date Published: June, 2022