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Okazaki, Soichiro*; Ezure, Toshiki; Ohshima, Hiroyuki; Kawara, Zensaku*; Yokomine, Takehiko*; Kunugi, Tomoaki*
Proceedings of 10th Pacific Symposium on Flow Visualization and Image Processing (PSFVIP-10), 8 Pages, 2015/06
A visualization study is performed under suction vortex geometry in water. In the experiment, the shear-sensitive liquid crystal coating (SSLCC) is applied to grasp the distribution of wall shear stress under the suction votex flow. As the result, it was found that the peak value of wall shear stress is appeared at the center and edge of the projected area of suction pipe. The non-dimensional profile of wall shear stress obtained by suction vortex flow experiment agrees well with that of numerical simulation.
Kunugi, Tomoaki*; Kawara, Zensaku*; Ose, Yasuo*; Ito, Kei; Sakai, Takaaki
Proceedings of 5th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-5), p.385 - 390, 2006/11
In order to design the compact FBR with higher coolant velocity compared to the conventional reactor designs, it is necessary to clarify a criterion of a cover gas entrainment (GE) from the free-surface of the coolant pool in the reactor vessel to the heat exchanger through the hot leg. Three flow regimes are considered as the GE phenomena: a vortex dimple, a waterfall and a surface disturbance. In this study, to evaluate the GE vortex phenomena: especially for the vortex dimple, the DNS based on the MARS (Multi-interfaces Advection and Reconstruction Solver (Kunugi, 2001)) were performed for simulating the unsteady vortex-shedding experiment accompanied with the GE phenomena (Okamoto et al., 2004). The applicability of the present DNS to predict the onset of the GE vortex phenomena is discussed.
