scholarly journals Effects of Soret and Dufour numbers on MHD thermosolutal convection of a nanofluid in a finned cavity including rotating circular cylinder and cross shapes

Author(s):  
Abdelraheem M. Aly ◽  
Shreen El-Sapa
1989 ◽  
Vol 9 (34) ◽  
pp. 273-276
Author(s):  
Takeyoshi Kimura ◽  
Michihisa Tsutahara ◽  
Zhong-yi Wang ◽  
Hiroshi Ishii

2021 ◽  
Author(s):  
Ehsanul Azim ◽  
Md. Jahid Hasan Sagor ◽  
Abul Borkot Md Rafiqul Hasan ◽  
Sumon Saha

2011 ◽  
Vol 133 (8) ◽  
Author(s):  
Dong-Hyeog Yoon ◽  
Kyung-Soo Yang ◽  
Klaus Bremhorst

Characteristics of turbulent mass transfer around a rotating circular cylinder have been investigated by Direct Numerical Simulation. The concentration field was computed for three different cases of Schmidt number, Sc = 1, 10 and 100 at ReR* = 336. Our results confirm that the thickness of the Nernst diffusion layer decreases as Sc increases. Wall-limiting behavior within the diffusion layer was examined and compared with that of channel flow. Concentration fluctuation time scale was found to scale with r+2, while the time scale ratio nearly equals the Schmidt number throughout the diffusion layer. Scalar modeling closure constants based on gradient diffusion models were found to vary considerably within the diffusion layer. Results of an octant analysis show the significant role played by the ejection and sweep events just as is found for flat plate, channel, and pipe flow boundary layers. Turbulence budgets revealed a strong Sc dependence of turbulent scalar transport.


This paper considers the two-dimensional flow past a circular cylinder immersed in a uniform stream, when the cylinder rotates about its axis so fast that separation in suppressed. The solution of the flow in the boundary layer on the cylinder is obtained in the form of a power series in the ratio of the stream velocity to the cylinder's peripheral velocity, and expressions are deduced for the value of the circulation and the torque on the cylinder. The terms calculated explicitly are sufficient to give reliable numerical values over the whole range of rotational speeds for which the postulate of non-separating flow is justifiable. The previously accepted theory, due to Prandtl, predicted that the circulation should not exceed a certain limit, while the present theory indicates that the circulation increases indefinitely with increase of rotaional speed. Strong arguments against the older theory are put forward, but the experimental evidence available is inconclusive.


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