IMAGES AND MOVIES GALLERY

Yifan Wang, Suncica Canic, Annalisa Quaini (UH)

Stephen Little, Matthew Jackson (Methodist Hospital Houston)

In Vitro and In Silico Coanda Effect in Mitral Valve Regurgitation

Mock Imaging Heart Chamber (Methodist Hospital Houston)

MRI-COMPATIBLE FLOW LOOP

3D SIMULATION OF IMAGING CHAMBER FLOW GIVING RISE TO COANDA EFFECT (University of Houston)

Y-COMPONENT OF VELOCITY (Peak Reynolds number = 3000)

VELOCITY MAGNITUDE

3D simulations of eccentric regurgitant flow were compared with 2D color Doppler image of the same flow in the 2nd-generation Mock Heart Chamber. Excellent agreement was achieved. The picture below shows a 2D slice of our 3D simulation (left) and a 2D color Doppler image of the same flow (right). Blue corresponds to backward flow (from top to bottom), while red corresponds to forward flow (bottom to top). A strong wall-hugging regurgitant jet can be observed in both pictures.



Our 3D flow simulations for the first time reveal that the regurgitant jet is actually spiraling away from the orifice, rather than flowing away from the orifice in an irrotational fashion. A vortex is generated downstream from the orifice, which, in 3D, generates vortex rolls. See Figure below. The vortex rolls push the regurgitant jet even closer to the wall. The spiraling motion of the jet gives rise to the regions of flow that are orthogonal to the imaging source, The particles in the region between the jet and the wall are entrained, pushing the jet even further to the wall. Due to the low velocity there, as well as on the vortex side, the jet appears smaller than it actually is, giving rise to the under estimation of the regurgitant volume based on the jet appearance on an echocardiographic image.



2D SIMULATION OF CHAMBER FLOW