Prosthetic heart valves are worldwide used in the clinical practice. Medical imaging allows the visualization of the flowfield through these devices with a limited spatio-temporal resolution. With the aim of unveiling both the complexity and beauty of such complex and hidden flow fields, Direct Numerical Simulation is adopted. In this way, one can accurately simulate the pulsatile flow, with moving and deforming geometries interacting with the fluid, observing transition to turbulence and then relaminarization, resolving all the scales down to the Kolmogorov one. Here two aortic valve models are considered in a rigid root: A bi-leaflet mechanical one, consisting of two properly constrained rigid leaflets, that move under the pressure gradient induced by the flow, and a biological tissue valve, with three deformable leaflets that closely mimics the natural case. The scope of this video is to reveal the different behavior of such flowfields, showing how these devices may induce non-physiological flow patterns, that are responsible for high shearing of blood cells and platelets. The finite-time Lyapunov exponent fields, showing Lagrangian coherent structures, help to visualize the Great Beauty of the physics involved in only 0.86 seconds of a heart beat.
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