Uppskattning av Ytkurvatur och CFD-simuleringar i Mänskliga Bukaortor
TechnologyAbdominal aortic aneurysmCurvature estimationCFDFLUENTGaussian curvatureModelingSegmentationWall shear stressTEKNIKVETENSKAP
By applying a segmentation procedure to two different sets of computed tomography scans, two geometrical models of the abdominal aorta, containing one inlet and two outlets have been constructed. One of these depicts a healthy blood vessel while the other displays one afflicted with a Abdominal Aortic Aneurysm. After inputting these geometries into the computational dynamics software FLUENT, six simulations of laminar, stationary flow of a fluid that was assumed to be Newtonian were performed. The mass flow rate across the model outlet boundaries was varied for the different simulations to produce a basis for a parameter analysis study. The segmentation data was also used as input data to a surface description procedure which produced not only the surface itself, but also the first and second directional derivatives in every one of its defining spatial data points. These sets of derivatives were followingly applied in an additional procedure that calculated values of Gaussian curvature. A parameter variance analysis was carried out to evaluate the performance of the surface generation procedure. An array of resultant surfaces and surface directional derivatives were obtained. Values of Gaussian curvature were calculated in the defining spatial data points of a few selected surfaces. The curvature values of a selected data set were visualized through a contour plot as well as through a surface map. Comparisons between the curvature surface map and one wall shear stress surface map were made.