Transient Analysis of Vortical Flows in Sigmoid Sinus Diverticulum Using Computational Fluid Dynamics

Author(s):  
Hui-Fang Lin ◽  
Yi-Chern Hsieh ◽  
Yue-Lin Hsieh
Author(s):  
Kuo-Ying Tsai ◽  
Shih-Chang Ku

A crack with unusual failure mode after thermal shock test (TST) is observed on the die bulk of certain bare-die FCBGA, in which the crack penetrates longitudinally within silicon die region. The computational fluid dynamics (CFD) method is introduced to investigate this phenomenon. The transient analysis results indicate a significant temperature difference existing between top and bottom surfaces of the silicon die in the very beginning of the liquid-to-liquid temperature transition. This could be fatal to a brittle material like silicon. Some possible solutions are then surveyed to alleviate the thermal impact to the FCBGA. At least one of enhanced proposals is proved effective to eliminate die crack occurrence after TST.


2017 ◽  
Vol 57 (8) ◽  
pp. 1360-1375 ◽  
Author(s):  
K. N. Volkov ◽  
V. N. Emel’yanov ◽  
I. V. Teterina ◽  
M. S. Yakovchuk

2021 ◽  
Vol 20 (1) ◽  
pp. 9
Author(s):  
Hangga Wicaksono ◽  
Sugeng Hadi Susilo ◽  
Bayu Pranoto ◽  
Muhammad Fakhruddin

The inconsistency of the wind flow considered as one of the factors which tend to decrease the performance of the wind turbine. This paper proposes a further analysis of the initial rotation characteristic of a hybrid Savonius - Darrieus wind turbine. The addition of the Darrieus blade intends to increase the aerodynamic stability of the overlapping Savonius turbine. This study implements 2D CFD transient analysis using the 6DOF methods in 0<sup>0</sup>, 30<sup>0</sup>, 60<sup>0</sup>, and 90<sup>0</sup> Darrieus blade position along with 2 m/s, 4 m/s, and 6 m/s wind speed variations. The results of the aerodynamic analysis show that the location of the Darrieus 30<sup>0</sup> turbine provides the greatest initial repulsion, especially when the turbine rotation is above 90<sup>0</sup>, the position of the Darrieus blade can provide additional impulse force when the Savonius turbine tends to be passive. This effect occurs more significant at higher wind speeds. Savonius with 3-blade modification has a more stable level of force distribution than the 2-blade modification, although the value is smaller. This shows that the 3-blade Savonius provide a higher stability of angular velocity development.


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