This work deals with the numerical simulation of interaction of fluid and vapor structures on NACA 2412 hydrofoil during the partial cavitation oscillation. This interaction is supposed to be the most important reason for the cavity shedding when, in a certain range of the cavitation numbers, some “resonance” effect can be reached. The incidence angle is 8? and the Reynolds number is 1.56 × 106. The hydrofoil with the span/chord ratio of 1.25 corresponds to the experiments carried out in the cavitation tunnel. The Detached Eddy Simulation (DES) is used on full 3D geometry of the straight NACA 2412 hydrofoil to capture the strong influence of side-wall effects. Real properties of water including estimated content of undissolved air are con-sidered to affect the compressibility of the mixture and its speed of sound. The link between strong pressure pulses during the cavity cycles and the interaction of fluid and vapor structures is discussed in detail.