Effects of transverse temperature gradient on acoustic and streaming velocity fields in a resonant cavity

2008 ◽  
Vol 93 (5) ◽  
pp. 051902 ◽  
Author(s):  
Majid Nabavi ◽  
Kamran Siddiqui ◽  
Javad Dargahi
2020 ◽  
Vol 10 (6) ◽  
pp. 1980 ◽  
Author(s):  
Lei Zhao ◽  
Ling-Yu Zhou ◽  
Guang-Chao Zhang ◽  
Tian-Yu Wei ◽  
Akim D. Mahunon ◽  
...  

To study the temperature distribution in the China Railway Track System Type II ballastless slab track on a high-speed railway (HSR) bridge, a 1:4 scaled specimen of a simply-supported concrete box girder bridge with a ballastless track was constructed in laboratory. Through a rapid, extreme high temperature test in winter and a conventional high temperature test in summer, the temperature distribution laws in the track on the HSR bridge were studied, and the vertical and transverse temperature distribution trend was suggested for the track. Firstly, the extreme high temperature test results showed that the vertical temperature and the vertical temperature difference distribution in the track on HSR bridge were all nonlinear with three stages. Secondly, the extreme high temperature test showed that the transverse temperature distribution in the track was of quadratic parabolic nonlinear form, and the transverse temperature gradient in the bottom base was significantly higher than that of the other layers of the track. Thirdly, the three-dimensional temperature distribution in the track on HSR bridge was a nonlinear, three-stage surface. Furthermore, similar regularities were also obtained in the conventional high temperature test, in which the temperature span ranges were different from those of the extreme high temperature test. In addition, the conventional high temperature test also showed that under the natural environment conditions, the internal temperature gradient in the track layers changed periodically (over a period of 24 h).


Author(s):  
А.В. Горбатюк ◽  
Б.В. Иванов

AbstractThe effects of a transverse temperature gradient in reversively switched-on dynistors have been studied. Taking into account these effects is important for high-voltage frequency dynistor assemblies because of the problems of a distributed cooling of the devices. A simulation description is given for the spatial dynamics of charges and heat in dynistor chips in switching of repeated current pulses. An estimation method is suggested for calculating the maximum repetition frequency coordinated with the heatsink heatsink cooling power.


Author(s):  
Hadi Babaei ◽  
Kamran Siddiqui

We report on an experimental study conducted to study the streaming velocity fields in the vicinity of the stack in a thermoacoustic device. Synchronized Particle Image Velocimetry (PIV) technique was used to measure the two-dimensional streaming velocity fields. The streaming velocity fields were measured at both sides of the porous stack over a range of pressure amplitudes (drive ratios). The results show that the streaming flow structure is significantly different on hot and cold sides of the stack. The hot side of the stack experienced higher magnitudes and higher spatial variability of the streaming velocities compared to the cold side. The difference in the velocity magnitude between the hot and cold sides of the stack showed a significant increase with an increase in the drive ratio.


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