This study considers some possibilities of CFD application in hydraulics. Design of hydraulic valves is a wide potential area for application of CFD, especially in respect of calculation of flow forces. These flow forces should be minimised during the optimisation and also determinable for a given pressure difference cr volume flow.Within the scope of this study some valve geometry were examined with respect to flow forces using CFD calculations. At first a conventional slide valve was calculated and detailed error analysis of CFD calculations of cavitating interior flow through valves were performed. Sequentially a compensated seated valve was calculated using two commercial CFD codes and two turbulence models. Finally a new unconventional valve geometry was examined and optimised with the aim to confirm the results of the error analysis previously carried out. The interior non-cavitating flow through this valve geometry was examined experimentally and theoretically using CFD.