Abstract
In order to indicate the complexity of signals in turbulent flows quantitatively, we used a concept of Kolmogorov complexity in computational science. The velocity data was compressed with the use of software for compression. The ratio of data size after compressed one to original one reflects the complexity of the data. Thus we named the ratio "Approximated Kolmogorov Complexity". The present analysis was applied to the laminar-turbulent transition process in a mixing layer formed at an exit of a two-dimensional nozzle and compared with the randomness factor which has been used for the measure of turbulent transition process in free shear flow. The randomness factor did not vary monotonically since it decreased at first and turned to increase following the progress of turbulent transition. On the other hand, approximated Kolmogorov complexity varied monotonically.
