ON THE FLOW-THROUGH THE HUMAN FEMALE URETHRA

The flow characteristic for a human female urethra is determined by di rect measurement of how rate and pressure difference data. The measure ments are made on a full-scale physical model of a urethra in its open state, which was created using dimensional information taken from vid eo cystograms. The measured data therefore include viscous dissipation effects associated with developing flow, changes in cross-sectional a rea and changes in how direction. These effects are often ignored in m athematical models of this system. The data may therefore assist in th e development and testing of more realistic models for urine flow. The measured characteristic is compared with a mathematical model of the flow based on a straight tube of uniform diameter carrying fully devel oped turbulent flow. When the diameter of the model tube is chosen to be equal to the distal diameter of the urethra, it is observed that th e predicted flow characteristic provides a good first approximation to the measured characteristic, despite the substantial differences in g eometry and flow regime between the mathematical model and the actual system. (C) 1997 Elsevier Science Ltd.