The fluid behavior in the tank of the cutting machine hydrostatic actuator is considered. The hydrodynamic simulation technique of such processes is described. The velocity magnitudes, temperature distribution fields and fluid flow lines trajectories in the tank volume analyzed. The tank configuration changes that allow to an increase its operational efficiency as the part of the hydraulic actuator are proposed. Recommendations for selecting tank optimal geometric dimensions in accordance with the criterion for the most even fluid flow rates distribution in the tank entire volume are presented.