We use telemetry data from the Gemini south multi-conjugate adaptive optics system (GeMS) to study the validity of the frozen Flow hypothesis using two types of algorithms: i) the spatio-temporal cross-correlations of the wave-front sensor (WFS) measurements; and ii) the Predictive Fourier Control (PFC) framework. The pros and cons of each technique are identified as well as their ability to determine the number of layers present and the associated velocities. Their potential use to determine the altitude, i.e. turbulence profiler, is also addressed. Examples derived from simulations and on-sky data are presented.