![]() High resolution measurement of turbulent structure in a channel with particle image velocimetry. Singapore: National Univeristy of Singapore, 1994, pp. In: Proceedings of the 8th International Conference on Biomedical Engineering, edited by J. Low, PIV measurements of flow past prosthetic heart valves. ![]() Improving the dynamic range of particle tracking velocimetry systems. Particle image velocimetry in the investigation of flow past artificial heart valves. In: Replacement Cardiac Valves, edited by E. Heart Valve Replacement and Future Trends in Cardiac Surgery. Shear induced aggregation and lysis of platelets. Baltimore: University Park Press, 1975, pp. In: Cardiovascular Flow Dynamics and Measurements, edited by N. In vitro flow dynamics of four prosthetic aortic valves: a comparative analysis. Turbulence downstream from the Ionescu-Shiley bioprosthesis in steady and pulsatile flow. California Institute of Technology, Ph.D. Fluid dynamics of Prosthetic Aortic Heart Valves in Steady and Pulsatile Flow. Pressure drop and velocity fields at mechanical heart valves. Membrane Strength-the Jet Fragility Test. Laser anemometry measurements of pulsatile flow past aortic valve prostheses. Study of vortex breakdown by particle tracking velocimetry (PTV). Although the PIV measurements may lack the accuracy of single-point measuring systems, the overall view of the flow in the aortic root region compensates for the shortcoming.īrucker, C., and W. The overall view of the velocity and stress mappings helps to identify regions of flow disturbances that otherwise may be lost with single-point measuring systems. High-velocity gradients were also measured at the interface of the jet and recirculating region in the sinus cavity. The development of the flow is further restricted by the valve stents, giving rise to stagnation regions and wakes. ![]() This in turn produces an intermixing zone between the central jet and recirculating region further downstream from the valve, which contributes to the high-stress zone measured. From our velocity and stress mappings, we found that the valve mounting ring effectively diminishes the central orifice area, giving rise to a higher central axial flow with strong recirculating regions and a corresponding large pressure drop. Coupled with flow visualization techniques, the hydrodynamic consequences of introducing a porcine bioprosthetic heart valve into the aortic root was examined, and compared with data obtained from an empty aortic root and an aortic root with the valve mounting ring alone. PIV is essentially a multipoint measurement technique that allows full-field measurement of instantaneous velocity vectors in a flow field, thus allowing us to map the entire velocity or stress field over the aortic root (where single-point measurements are difficult). The purpose of this study is to map the velocity vector fields and Reynolds stresses downstream of a porcine bioprosthetic heart valve in the aortic root region with particle image velocimetry (PIV) techniques in vitro under steady flow conditions. These parameters have previously been evaluated using single-point measurement techniques such as laser Doppler anemometry (LDA). Velocity profiles and Reynolds stresses downstream of heart valve prostheses are vital parameters in the study of hemolysis and thrombus formation associated with these valves. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |