Ventricular assist devices (VADs) are actively used for congestive heart failure and myocarditis patients but clinical issues, such as thrombosis, still remain as work continues toward development as destination therapy devices. As Penn State continues to develop smaller generation VADs, the role of experimental fluid dynamics has increased as the capability to predict thrombus deposition using wall shear estimates has improved based on animal studies. These experimental data are leading towards the development of computational simulations to identify areas not easily visualized experimentally. Particle image velocimetry, an optical measurement technique, has been adapted and the resulting velocity data, post-processed, to extract wall shear rates throughout different areas of adult (50cc) and pediatric (12cc) VADs. The results indicate areas susceptible to thrombosis and where subsequent VAD design changes have improved the flow with adequate wall shear. The role of experimental fluid dynamic measurements have greatly improved our ability to predict areas of thrombus deposition leading to improved VAD designs, provide a foundation for computer simulations with correlations to in vivo animal testing.