Abstract:
A study of involuntary micturition (urine flow) in a slowly varying urethral diameter precipitated by an intense urge to urinate have been considered. The urethra have been assumed to be cylindrical in shape; and elastic since its made up of muscles. Even though the urethra is elastic, the pressure causing voiding is not enough to stretch the urethral walls. Thus no movement of the urethral walls during voiding implies the velocity profile is in axial direction with distance along the urethra called the axial distance. Consequently, the Navier-Stokes equation which describes the axial motion was solved to obtain an expression for velocity and pressure along the urethra assuming there is no abnormality in the Lower Urinary Tract (LUT) and that the urine is already stored in the bladder. Asymptotic limit to determine the expression for urethral axial velocity close to the end of micturition process was also considered.
