跳至主要内容

Visualization of Traveling Vortices in the Boundary Layer on a Rotating Disk under Orbital Motion

Read  full  paper  at:
http://www.scirp.org/journal/PaperInformation.aspx?PaperID=54088#.VO1zISzQrzE

ABSTRACT
The objective of this study is to experimentally visualize traveling vortices in the boundary layer on a rotating disk under orbital motion. The orbital radius is half of the disk’s diameter (200 mm) and the maximum speed of orbital motion is 500 revolutions per minute. The Reynolds number in the pure-rotation case is 2.77 × 105. The characteristics of two types of traveling vortices are visualized by a smoke-wire method. The first type is transition vortices. In the pure-rotation case, they arise at circumferentially equal intervals, and are not traveling but stationary relative to the rotational disk. The result of visualization of this type shows that the intervals between transient vortices change in a circumferential direction, or in an orbital radial direction, on the rotating disk under orbital motion. The second type is new arc-shaped vortices that correspond to low-frequency disturbances. As orbital speed increases, the radial traveling velocities of the low-frequency disturbances increase and the intervals between low-frequency disturbances decrease.
 
Cite this paper
Munekata, M. , Kubo, K. and Yoshikawa, H. (2015) Visualization of Traveling Vortices in the Boundary Layer on a Rotating Disk under Orbital Motion. Open Journal of Fluid Dynamics, 5, 17-25. doi: 10.4236/ojfd.2015.51003.
 
References
[1]Reed, H.L. and Saric, W.S. (1989) Stability of Three Dimensional Boundary Layers. Annual Review of Fluid Mechanics, 21, 235-284.
http://dx.doi.org/10.1146/annurev.fl.21.010189.001315
 
[2]Gregory, N., Stuart, J.T. and Walker, W.S. (1955) On the Stability of Three-Dimensional Boundary Layers with Application to the Flow Due to a Rotating Disk. Philosophical Transactions of the Royal Society of London, A248, 155-199.
http://dx.doi.org/10.1098/rsta.1955.0013
 
[3]Kohama, Y. (1984) Study on Boundary Layer Transition of a Rotating Disk. Acta Mechanica, 50, 193-199.
http://dx.doi.org/10.1007/BF01170959
 
[4]Schlichting, H. (1955) Boundary-Layer Theory. McGraw-Hill, New York, 83-89.
 
[5]Von Kármán, T. (1921) über laminare und turbulnte Reibung. Zeitschrift für Angewandte Mathematik und Mechanik, 1, 233-252.
http://dx.doi.org/10.1002/zamm.19210010401
 
[6]Kobayashi, R., Kohama, Y. and Takamadate, Ch. (1980) Spiral Vortices in Boundary Layer Transition Regime on a Rotating Disk. Acta Mechanica, 35, 71-82.
http://dx.doi.org/10.1007/BF01190058
 
[7]Munekata, M., Jobi, N., Ikebe, K. and Yoshikawa, H. (2012) Effects of Orbital Motion on the Boundary Layer Flow on a Spinning Disk. Open Journal of Fluid Dynamics, 2, 181-186.
http://dx.doi.org/10.4236/ojfd.2012.24A020
 
[8]Munekata, M., Jobi, N., Kubo, K. and Yoshikawa, H. (2013) Characteristics of Transient Vortices in the Boundary Layer on a Rotating Disk under Orbital Motion. Journal of Thermal Science, 22, 600-605.
http://dx.doi.org/10.1007/s11630-013-0668-0
 
[9]Malik, M.R., Wilkinson, S.P. and Orszag, S.A. (1981) Instability and Transition in Rotating Disk Flow. AIAA Journal, 19, 1131-1138.
http://dx.doi.org/10.2514/3.7849                                        eww150225lx
标签：

评论

发表评论

此博客中的热门博文

Does Immigration Promote the Investment of the Monopolistic Firm?

In the present paper, we examine the effect of increasing uncertainty of immigrants’ growth on the optimal timing of investment of a firm that has a monopolistic power over the labor market. It is revealed that when the uncertainty of immigrants’ growth is more than a threshold level, increasing uncertainty of immigrants’ growth accelerates the optimal timing of firms’ investment and enhances the economic growth, even if the uncertainty of immigrants’ growth is formulated by the geometric Brownian motion, which is in sharp contrast to the standard result that an increase in the uncertainty postpones the optimal timing. With an increase in the immigrants over the past ten years, workforces in the host countries have been growing significantly to the extent that the immigrants represent 70% of the increase in the workforce in Europe, and 47% in the United States as OECD indicates. In the present paper, we attempted to investigate the effect of increased uncertainty caused by the growi...
发表评论
阅读全文

Education Policy Implementation: A Mechanism for Enhancing Primary Education Development in Zanzibar

Education is one of the fundamental rights of individuals; therefore, the government of a country needs to develop and strengthen educational policy and quality as well as to ensure that everyone has equal access to basic education. The improvement of access and quality of education in the world is becoming as an essential factor in development, whereas the basic education (primary school), is acknowledged as a foundation of the higher educational development for every country. To fulfill this goal, governments introduce several policies and procedures; however, it requires some reforms and participation from the politician, policymakers, and other stakeholders to re-examine educational policy so that it can lead to multiplication and betterment of the reforms. Educational reforms actually focus on accountability. A positive educational development and reform is very challenging and needs more effort and strategy on how to use and utilize the resources effectively as such it can achie...
发表评论
阅读全文