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Unnatural temporal and spatial distributions of wall shear stress in the anastomosis of distal bypass grafts have been identified as possible factors in the development of anastomotic intimal hyperplasia in these grafts. Distal bypass graft anastomoses with an autologus vein cuff (a Miller cuff) interposed between the graft and artery have been shown to alleviate the effects of intimal hyperplasia. In this study, pulsatile flow through models of a standard end-to-side anastomosis and a Miller cuff anastomosis are computed and the resulting wall shear stress and pressure distributions analysed. The results are inconclusive, and could be taken to suggest that the unnatural distributions of shear stress that do occur along the anastomosis floor may not be particularly important in the development of intimal hyperplasia. However, it seems more likely that the positive effects of the biological and material properties of the vein cuff, which are not considered in this study, somehow outweigh the negative effects of the shear stress distributions predicted to occur on the floor of the Miller-cuff graft.

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<div class="section abstract"><div class="htmlview paragraph">Traditionally, ground vehicle aerodynamics has been researched with highly simplified models such as the Ahmed body and the SAE model. These models established and advanced the fundamental understanding of bluff body aerodynamics and have generated a large body of published data, however, their application to the development of passenger vehicles is limited by the highly idealized nature of their geometries. To date, limited data has been openly published on aerodynamic investigations of production vehicles, most likely due to the proprietary nature of production vehicle geometry. In 2012, Heft et al. introduced the realistic generic car model ‘DrivAer’ that better represents the flow physics associated with a typical production vehicle. The introduction of the DrivAer model has led to a broad set of published data for both experimental and computational investigations and has proven itself invaluable as a correlation and calibration tool of wind tunnels, the validation of computational fluid dynamics (CFD) codes and increasing the understanding of the fundamental flow physics around passenger vehicles.</div><div class="htmlview paragraph">Automotive sales trends in the United States, published by the Bureau of Economic Analysis in 2018, indicate that sales of Pickup Trucks (PUs) and Sports Utility Vehicles (SUVs) have increased over the past 10 years and are outselling sedans at a rate just over two to one. Compared to sedans, PU and SUV body styles pose additional aerodynamic challenges due to their complex wake structures. The introduction of a realistic generic PU and SUV model as an open access tool is expected to yield benefits to the wider community, equivalent to those of the DrivAer passenger vehicle. This paper introduces the Generic Truck Utility (GTU) as a realistic, generic PU truck and interchangeable SUV model. The paper will focus on the design and development of the GTU and will present a summary of preliminary experimental results of the GTU complemented by numerical simulations using iconCFD®, an open source based CFD solver.</div></div>