A mathematical model of an axial piston pump is presented. The numerical model is based on a finite volume concept. The pump has been divided in different volumes where fluid properties are assumed homogeneous. Since the reduction of the pressure pulsations is one of the most important aims of pump builders, the effects of the port plate relief groove design have been carefully modelled. The gaseous cavitation has been considered in a simplified manner. The pump has been modified in order to measure the fluid pressure inside one of the cylinders; therefore a conduit has been realized to connect the cylinder chamber to a pressure transducer that is placed in a non-rotating position. The fluid pressure inside the conduit has been modelled with a one dimensional scheme for unsteady flow. The code has been tested and calibrated by comparing its numerical results with a set of experimental data. The potentials of the code are presented, spanning over different geometries.Copyright © 2002 by ASME