Method for detector description transformation to Unity and application in BESⅢ

Detector and event visualization are essential parts of the software used in high-energy physics(HEP)experiments.Modern visualization techniques and multimedia production platforms such as Unity provide impressive display effects and professional extensions for visualization in HEP experiments.In this study,a method for automatic detector description transformation is presented,which can convert the complicated HEP detector geometry from GDML in offline software to 3D modeling in Unity.The method was successfully applied in the BESIII experiment and can be further developed into applications such as event displays,data monitoring,or virtual reality.It has great potential in detector design,offline software development,physics analysis,and outreach for next-generation HEP experiments as well as applications in nuclear techniques for the industry.

Estimation of the turbulent viscous shear stress in a centrifugal rotary blood pump by the large eddy particle image velocimetry method

The non-physiologic turbulent flows in centrifugal rotary blood pumps (RBPs) may result in complications such as the hemolysis and the platelet activation. Recent researches suggest that the turbulent viscous dissipation in the smallest eddies is the main factor of the blood trauma caused by the turbulent flow. The turbulent viscous shear stress (TVSS) was taken as the realistic physical force acting on the cells. However, limited by the temporal and spatial resolutions of the instrumentation currently available, very limited studies are available for the TVSS in the RBPs. In this paper, the large eddy particle image velocimetry (PIV) method is used to estimate the turbulent dissipation rate in the sub-grid scale, to investigate the effect of the TVSS on the blood trauma. Detailed flow characteristics, such as the relative velocity vectors, the estimated TVSS levels and the Kolmogorov length scales, are analyzed in three impeller phases at three constant flow rates (3 L/min, 5 L/min and 7 L/min). Over the measures range in this study, the maximum TVSS in the investigated RBP is lower than the reported critical value of stress. This study demonstrates that the large eddy PIV method is effective to evaluate the flow-dependent force on the cells. On the other hand, it is found that the TVSS is highly dependent on the flow behavior. Under severe off-design conditions, the complex flow characteristics, such as the flow separation and the vortical structures, will increase the TVSS. Thus, in order to reduce the hemolysis in the RBPs, the flow disturbance, induced by the departure of the incidence angle, should be avoided during the design of the RBPs.