Movie S2 from Enhanced wall shear stress prevents obstruction by astrocytes in ventricular catheters

Direct flow visualization at a hole closest to the valve, using fluorescent particle tracking by high-speed microscopy. An actual catheter (Codman EDS 3 Clear Ventricular CSF Catheter, Codman & Shurtleff ) was used. The refractive index of the working fluid was matched to that of the catheter material so that optical distortion that can originate from the curvature of the catheter-fluid interface was eliminated. The left and right videos generate the pathlines in Figure 11b and 11c of the main article, respectively. Note that the flow at the hole entrance, shown in the left video, is not the uniform flow that is typically assumed in the classical entrance length estimation. Using this visualization technique, we measured 3D velocity profiles inside the catheter as described in Figure 12 of the main article. Here, the Reynolds number, defined by equation (1) in the article, is 0.5. The videos play 0.2x.