The results are reported of a combined experimental and computational study of steady flow through an axisymmetric valve/port assembly, the main objective of which was to assess the accuracy of the multidimensional model predictions of this flow. Measurements of the discharge coefficient, mean velocity and the turbulent Reynolds stress fields were obtained by hot-wire anemometry at various valve lifts. These were supplemented by flow visualisation studies. Predictions were made using a finite-volume method employing a body-fitted computational mesh and the k-ε turbulence model. Good agreement was found at low lifts, but at higher values this deteriorated due to the inability of the turbulence model to provoke the flow separations which occurred in the experiments. The conclusion is that for both idealised and practical ports multidimensional predictions will be of limited accuracy until better turbulence models become available.