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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

A Numerical Study of g-jitter Effects on Cubic-Cavity Convection in Low Gravity

Get access (open in a dialog) DOI: 10.1615/IHTC15.ncv.008624
pages 5387-5402

要約

In this study, the authors numerically investigate the forced-oscillation-frequency responses on the three-dimensional thermal convection in a cubic cavity heated from one wall and chilled from its opposite wall in the non-gravitational field with a vibrational Rayleigh number Ra? = 5.0×103 – 1.1×105, a Plandtl number Pr = 7.1 (water) and nondimensional forced-oscillation frequency ? = 1.0×100 – 1.0×103. The direction of the forced sinusoidal oscillation is parallel to the temperature gradient inside the cubic cavity. The authors especially focus upon the influences of both Ra? and ?. As a result, four kinds of structures S2, S4, S5 and S6 appear in the tested ranges of Ra? and ?. And, such flow structures are revealed in detail. Whenever it is not conductive but convective for ? < 5.0×102, convective motion always starts with the S4 from the rest at each forcing cycle. The authors find out the optimum frequency K max ???? where the amplitude of a spatially-averaged kinetic energy K , which is defined by the difference between the maximum K and the minimum K over one forcing cycle, attains the maximum at each Ra?. At ? = K max ???? , the flow structure is characterised by the S4. So, this fact suggests that the optimum frequency can be related with the S4. In addition, the authors show the occurrence condition for convection as a function of Ra? and ?, and the boundary for the quasi-steady approximation which is permissible at ? ???? 100 from a quantitative viewpoint.