Abstract
The spatio-temporal differential method(gradient method) can be one of the high precision algorithms for PIV analysis. But, when the method is applied to actual PIV pictures, measurement precision cannot be so good as is expected. It is found that inadequate numerical differentiations and peak-locking phenomenon degrade its intrinsic characteristics. The first issue is discussed in a separate paper. In this paper, the peak-locking phenomena for PTV with various picture conditions and influences of interpolation methods on the phenomenon are examined and discussed. Some methods to reduce the peak-locking error are recommended, and the precision of less than 0.05 pixel ambiguity could be realized.
