The shape of the urine stream — from biophysics to diagnostics
The shape of the urine stream — from biophysics to diagnostics
We develop a new computational model of capillary-waves in free-jet flows, and apply this to the problem of urological diagnosis in this first ever study of the biophysics behind the characteristic shape of the urine stream as it exits the urethral meatus. The computational fluid dynamics model is used to determine the shape of a liquid jet issuing from a non-axisymmetric orifice as it deforms under the action of surface tension. The computational results are verified with experimental modelling of the urine stream. We find that the shape of the stream can be used as an indicator of both the flow rate and orifice geometry. We performed volunteer trials which showed these fundamental correlations are also observed in vivo for male healthy volunteers and patients undergoing treatment for low flow rate. For healthy volunteers, self estimation of the flow shape provided an accurate estimation of peak flow rate (+-2%). However for the patients, the relationship between shape and flow rate suggested poor meatal opening during voiding. The results show that self measurement of the shape of the urine stream can be a useful diagnostic tool for medical practitioners since it provides a non-invasive method of measuring urine flow rate and urethral dilation.
e47133-[7pp]
Wheeler, Andrew P.S.
0f243ba3-3aae-470c-ba4a-46a8c4b9197a
Morad, Samir
8cb59f3d-3ce5-46a3-b33e-89d14cebcf98
Buchholz, Noor
0e883077-ba17-4fa5-aa21-4bd1f6ea2be9
Knight, Martin M.
03701351-a8b9-4b66-8237-fca60c6b5412
2012
Wheeler, Andrew P.S.
0f243ba3-3aae-470c-ba4a-46a8c4b9197a
Morad, Samir
8cb59f3d-3ce5-46a3-b33e-89d14cebcf98
Buchholz, Noor
0e883077-ba17-4fa5-aa21-4bd1f6ea2be9
Knight, Martin M.
03701351-a8b9-4b66-8237-fca60c6b5412
Abstract
We develop a new computational model of capillary-waves in free-jet flows, and apply this to the problem of urological diagnosis in this first ever study of the biophysics behind the characteristic shape of the urine stream as it exits the urethral meatus. The computational fluid dynamics model is used to determine the shape of a liquid jet issuing from a non-axisymmetric orifice as it deforms under the action of surface tension. The computational results are verified with experimental modelling of the urine stream. We find that the shape of the stream can be used as an indicator of both the flow rate and orifice geometry. We performed volunteer trials which showed these fundamental correlations are also observed in vivo for male healthy volunteers and patients undergoing treatment for low flow rate. For healthy volunteers, self estimation of the flow shape provided an accurate estimation of peak flow rate (+-2%). However for the patients, the relationship between shape and flow rate suggested poor meatal opening during voiding. The results show that self measurement of the shape of the urine stream can be a useful diagnostic tool for medical practitioners since it provides a non-invasive method of measuring urine flow rate and urethral dilation.
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e-pub ahead of print date: 16 October 2012
Published date: 2012
Organisations:
Aeronautics, Astronautics & Comp. Eng
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Local EPrints ID: 346883
URI: http://eprints.soton.ac.uk/id/eprint/346883
ISSN: 1932-6203
PURE UUID: 840db5a6-79a3-477a-8e2d-ca4ac6fb6799
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Date deposited: 15 Jan 2013 16:47
Last modified: 14 Mar 2024 12:42
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Contributors
Author:
Andrew P.S. Wheeler
Author:
Samir Morad
Author:
Noor Buchholz
Author:
Martin M. Knight
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