Laminar to turbulent transition under physiological conditions

MSc graduation project of Renzo Trip (current function: PhD student KTH Sweden)
Location: Lab. for Aero & Hydrodynamics
Supervisor: C. Poelma, R. Delfos
Defense: October 28 2010

Project description:

Under normal conditions, blood flow is laminar. However, diseases like aortic stenosis might cause the blood flow to become turbulent. Turbulent blood +flow is known to be a health risk. Therefore, it is interesting to know under which physiological conditions transition from laminar to turbulent occurs. Previous research has shown pulsatile blood flow is more stable compared to steady flow. Goal of this thesis project is to find a relation between +frequency and the critical Reynolds number and to get a better understanding why transition occurs at higher Reynolds numbers than would be the case for steady flow. The blood flow is approximated by a pulsatile, sinusoidal inlet velocity with characteristic amplitude, frequency and positive mean flow. These parameters will be described by dimensionless Reynolds numbers and the Womersley number. An experimental setup is build using a gear pump to obtain the desired pulsatile flow. Main part of this setup is an 5m Perspex pipe, 4cm in diameter. A settling chamber is designed to have well known entrance conditions. An orifice plate will be used as a trigger mechanism. Measurements are done using 2D-Particle Image Velocimetry (PIV).


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