A Novel Semi-Passive Turbulence Enhancement Method: A Flexible Vortex Generator

The turbulence enhancement ability of a flexible vortex generator (FVG) was numerically studied in this research. The spatial and turbulence characteristics of the wake of the FVG that is submerged in a subcritical flow were examined. The FVG’s heat transfer performance was also investigated. In general, the analyses show that the FVG has a better turbulence generation ability that is caused by the escalated shear, which is proportional to the FVG’s structural velocity

FSI SIMULATION OF A FLEXIBLE VORTEX GENERATOR AND THE EFFECTS OF VORTICES TO THE HEAT TRANSFER PROCESS

This work numerically investigated the strength of vortices behind a flexible vortex generator (FVG) by calculating the circulation using Fluid-Structural Interaction (FSI) simulation of RANS (SST) k-ω model. The total circulation showed the vortices formed by the FVG was more significant than those originated by the rigid vortex generator (RVG). From the analyses, the case with more significant structural velocity results in a larger shear or circulation. The structural velocity computation proves an excellent consistency with the model predicted values. This has suggested the reliability of the proposed model. Therefore, the performance of FVG in turbulence augmentation has been identified, suggesting enhanced turbulent transport for the greater heat transfer process. Next, the numerical model was extended to examine the heat transfer performance of the FVG. In general, the findings show that the employment of the FVG has a significant positive impact on the heat transfer process in the heat exchanger

A comparison between the effectiveness of a gamified approach with the conventional approach in point-of-care ultrasonographic training

Background Although gamification increases user engagement, its effectiveness in point-of-care ultrasonographic training has yet to be fully established. This study was conducted with the primary outcome of evaluating its effectiveness in point-of-care ultrasonographic training as compared to conventional approach. Methods Participants consisting of junior doctors were randomized into either the (1) gamified or the (2) conventional educational approach for ultrasonographic training. Results A total of 31 junior doctors participated in this study (16 participants in gamified arm, 15 in the conventional arm after one participant from the conventional arm dropped out due to work commitment). Two-way mixed ANOVA test showed that there was no statistically significant interaction between the types of educational approach and time of testing (pre-test, post-test, 2 months post-training) for both theoretical knowledge score and practical skills score, with F(2, 58) = 39.6, p < 0.001, partial η2 = 0.4 and F(2, 58) = 3.06, p = 0.06, partial η2 = 0.095, respectively. For theoretical knowledge score, pairwise comparisons showed that the mean 2 months post-training scores (20.28 +/− 0.70, 95% CI 18.87–21.69) and mean post-test scores (20.27 +/− 0.65, 95% CI 18.94–21.60) were better than the pre-test scores (12.99 +/− 0.50, 95% CI 11.97–14.00) with p-values < 0.001 for both comparisons respectively. Similarly, for practical skill score, pairwise comparisons showed that the mean 2 months post-training scores (20.28 +/− 0.70, 95% CI 18.87–21.69) and mean post-test scores (20.27 +/− 0.65, 95% CI 18.94–21.60) were also better than the pre-test scores (12.99 +/− 0.50, 95% CI 11.97–14.00) with p-values < 0.001 for both comparisons respectively. Participants in the gamification arm generally perceived the various game elements and game mechanics as useful in contributing and motivating them to learn ultrasonography. Conclusions Gamification approach could be an effective alternative to conventional approach in point-of-care ultrasonographic training

Turbulence Characteristics of the Flexible Circular Cylinder Agitator

A flexible protruding surface was employed as the flow disturbance to promote turbulence at the area of interest. An ultrasonic velocity profiler, UVP technique, was used to study the mean and fluctuating flow properties in the near wake of the rigid and flexible protruding surface in a water tunnel. The polymer based, ethylene-vinyl acetate (EVA) with an aspect ratio of AR = 10, 12, 14, 16 was used as the flexible circular cylinder, and submerged in a flow at Re = 4000, 6000 and 8000. The motion of the cylinder altered the fluid flow significantly. As a means to quantify turbulence, the wakes regions and production terms were analyzed. In general, the flexible cylinders show better capability in augmenting the turbulence than the rigid cylinder. The results show that the turbulence production term generated by the flexible cylinder is higher than that of rigid cylinder. The localized maximum shear production values have increased significantly from 131%, 203% and 94% against their rigid counterparts of AR = 16 at the Re = 4000, 6000 and 8000, respectively. The performance of turbulence enhancement depends heavily on the motion of the cylinder. The findings suggest that the turbulence enhancement was due to the oscillation of the flexible cylinder. The results have concluded that the flexible cylinder is a better turbulence generator than the rigid cylinder, thus improving the mixing of fluid through augmented turbulent flow