Numerical Study of G-Jitter Effects on Thermal Instability and Natural Convection Heat Transfer

• Main Authors: Chen-Yu Su, 蘇震宇
• Other Authors: Chyi-Yeou Soong
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/84372449241373717253

碩士 === 中正理工學院 === 兵器工程研究所 === 86 === ABSTRACT The objective of the present investigation is to explore the influences of g-jitter effect on threshold of thermal instability and natural convection flow structure and heat transfer. By invoking Boussinesq approximation , the governing equations are cast into a form of velocity-vorticity formulation , and then solved on a uniform staggered grid by a numerical procedure based on central difference scheme. The physical model considered is air of Pr=0.71 in a rectangular enclosure of width-to-length aspect ratio 4:1. The enclosure is heated from below and of two side-walls insulated.Firstly,thermal instability in horizontal enclosure with g-jitter of various amplitudes and frequencies is investigated. In the second part , the gravity modulation effects on flow structure and heat transfer performance are studied. The results show that the g-jitter effects delay the onset of thermal instability and the effect is maximun at the high amplitude and middle frequency. The results also reveal that the thermo-flow characteristics can be strongly influenced by the g-jitter effects especially that of low frequency and large amplitude.