Installations involving fluids often present problems in terms of the dynamic performances of their different parts. These problems can be analysed and dealt with at the design stage. This means that both the technologists who design the thermohydraulic process and those who carry out the regulation and control must be involved in the process from the early stages of the design. In this study, a dynamic model of the behaviour of a gas flowmeter has been developed, based on the laws of conservation of mass, linear momentum, energy and angular momentum. The model has been computerised via a software module. As there is no information available with which to compare the model's behaviour, a continuous rating validation has been carried out, using a comparison with the actual calibration curve of the flowmeter. The results obtained are satisfactory. (c) 2006 Elsevier Ltd. All rights reserved.