Context. According to the modern cosmological paradigm, galaxies and galaxy systems form from tiny density perturbations generated during the very early phase of the evolution of the Universe. Aims. Using numerical simulations, we study the evolution of the density perturbation phases of different scales to understand the formation and evolution of the cosmic web. Methods. We apply the wavelet analysis to follow the evolution of high-density regions (clusters and superclusters) of the cosmic web. Results. We show that the maxima and minima positions of density waves (their spatial phases) almost do not change during the evolution of the structure. Positions of density perturbation extrema of are more stable for larg...