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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Scaling and intermittency of velocity fluctuations in turbulent convection. / 湍流對流中速度漲落量之標度律與間歇性 / Scaling and intermittency of velocity fluctuations in turbulent convection. / Tuan liu dui liu zhong su du zhang luo liang zhi biao du lü yu jian xie xing

January 2004 (has links)
Leung Chun Kit = 湍流對流中速度漲落量之標度律與間歇性 / 梁振傑. / Thesis submitted in: 31st October, 2003. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 69-71). / Text in English; abstracts in English and Chinese. / Leung Chun Kit = Tuan liu dui liu zhong su du zhang luo liang zhi biao du lü yu jian xie xing / Liang Zhenjie. / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Rayleigh-Benard Convection Experiment --- p.6 / Chapter 2.1 --- Rayleigh-Benard convection --- p.6 / Chapter 2.2 --- Experimental measurements --- p.7 / Chapter 3 --- Probability Density Functions of Velocity Differences --- p.10 / Chapter 3.1 --- Important time scales --- p.11 / Chapter 3.2 --- PDF calculation --- p.13 / Chapter 3.3 --- Results --- p.14 / Chapter 4 --- Characterization of Velocity Intermittency --- p.23 / Chapter 4.1 --- SL hierarchy for the velocity fluctuations --- p.23 / Chapter 4.2 --- Checking SL hierarchy --- p.24 / Chapter 4.3 --- Results --- p.25 / Chapter 5 --- The Most Intense Velocity Structures --- p.45 / Chapter 5.1 --- The most intense velocity structures and the parameters a and b --- p.45 / Chapter 5.2 --- Estimating the parameters a and b --- p.46 / Chapter 5.3 --- Results --- p.47 / Chapter 5.4 --- Checking a conjecture --- p.63 / Chapter 6 --- Conclusion --- p.67 / Bibliography --- p.69
72

Experimental investigation of high prandtl number turbulent convection. / 高普朗特數湍流對流的實驗硏究 / Experimental investigation of high prandtl number turbulent convection. / Gao pu lang te shu tuan liu dui liu de shi yan yan jiu

January 2000 (has links)
Lam Siu = 高普朗特數湍流對流的實驗硏究 / 林霄. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 97-100). / Text in English; abstracts in English and Chinese. / Lam Siu = Gao pu lang te shu tuan liu dui liu de shi yan yan jiu / Lin Xiao. / Abstract (in English) --- p.i / Abstract (in Chinese) --- p.ii / Acknowledgements --- p.iii / Table of Contents --- p.iv / List of Figures --- p.vi / List of Tables --- p.ix / Chapters / Chapter I. --- Introduction --- p.1 / Chapter II. --- Turbulent Rayleigh-Benard Convection --- p.5 / Chapter 2.1 --- Rayleigh-Benard Convection --- p.5 / Chapter 2.2 --- The Convection Equations --- p.6 / Chapter 2.3 --- The parameters --- p.7 / Chapter 2.4 --- Recent Developments --- p.9 / Chapter 2.4.1 --- Heat Transport --- p.9 / Chapter 2.4.2 --- Large-scale Circulation and thermal Plumes --- p.11 / Chapter 2.4.3 --- Boundary Layers --- p.12 / Chapter III. --- Experimental Setup and Methods --- p.15 / Chapter 3.1 --- The Apparatus --- p.15 / Chapter 3.2 --- The Working Fluids --- p.18 / Chapter 3.3 --- Thermal Measurements --- p.23 / Chapter 3.4 --- Flow Visualization --- p.26 / Chapter IV. --- Heat Transport in Turbulent Convection --- p.29 / Chapter 4.1 --- The Non-Boussinesq Effect --- p.30 / Chapter 4.2 --- Experimental Results --- p.34 / Chapter 4.2.1 --- 1-Pentanol --- p.35 / Chapter 4.2.2 --- Triethylene Glycol --- p.36 / Chapter 4.2.3 --- Results from Dipropylene Glycol --- p.37 / Chapter 4.3 --- Discussion on the Results --- p.38 / Chapter 4.4 --- Summary --- p.43 / Chapter V. --- Local Temperature Measurements --- p.45 / Chapter 5.1 --- Temperature Time Series and Histograms --- p.45 / Chapter 5.2 --- Mean Temperature Profiles and Thermal Boundary Layers --- p.55 / Chapter 5.3 --- RMS Profiles --- p.58 / Chapter 5.4 --- Skewness Profiles --- p.65 / Chapter 5.5 --- Summary --- p.68 / Chapter VI. --- Measurements on the Viscous Boundary Layers --- p.70 / Chapter 6.1 --- Power Spectrum --- p.70 / Chapter 6.2 --- Two-Probe Cross-correlation --- p.76 / Chapter 6.3 --- Laser Light Scattering --- p.84 / Chapter 6.4 --- Summary --- p.90 / Chapter VII --- . Conclusions --- p.93 / References --- p.97
73

Conditional temperature structure functions in turbulent convection. / 對流湍流中條件溫度結構函數之硏究 / Conditional temperature structure functions in turbulent convection. / Dui liu tuan liu zhong tiao jian wen du jie gou han shu zhi yan jiu

January 2000 (has links)
Chau Kwok Leung = 對流湍流中條件溫度結構函數之硏究 / 周國良. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves [93]-94). / Text in English; abstracts in English and Chinese. / Chau Kwok Leung = Dui liu tuan liu zhong tiao jian wen du jie gou han shu zhi yan jiu / Zhou Guoliang. / Abstract --- p.i / Abstract (Chinese Version) --- p.ii / Acknowledgement --- p.iii / Table of contents --- p.iv / List of figures --- p.v / List of tables --- p.xiii / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Rayleigh Benard experiments --- p.6 / Chapter 2.1 --- Rayleigh-Benard Experiment --- p.6 / Chapter 2.2 --- Rayleigh-Benard Convection using Helium --- p.8 / Chapter 2.3 --- Rayleigh-Benard Convection Experiment using water --- p.9 / Chapter 2.4 --- Passive Temperature Measurements in a Wind Tunnel Experiment --- p.10 / Chapter 3 --- Conditional Probability density function of the Temperature Differences --- p.11 / Chapter 3.1 --- Approximation of locally averaged temperature dissipation rate --- p.12 / Chapter 3.2 --- Conditional PDF for r < Tb --- p.14 / Chapter 3.3 --- Conditional PDF for r > Tb --- p.18 / Chapter 4 --- Conditional Statistics of Temperature Difference --- p.26 / Chapter 4.1 --- Distribution of In xT --- p.26 / Chapter 4.2 --- XT-dependence of 〈\TT\P\XT〉 --- p.28 / Chapter 4.2.1 --- Xr-dependence for small T --- p.28 / Chapter 4.2.2 --- XT dependence for large T --- p.31 / Chapter 4.3 --- "m(T,P)" --- p.39 / Chapter 4.4 --- Consequence of the Standard Gaussian Conditional PDF for T >Tb --- p.53 / Chapter 4.5 --- c(T,p) --- p.57 / Chapter 4.5.1 --- T>Tb --- p.60 / Chapter 4.5.2 --- T>Tb --- p.64 / Chapter 5 --- Height dependence of Conditional Temperature Structure Function --- p.69 / Chapter 5.1 --- Determination of rc and Td --- p.69 / Chapter 5.2 --- Height dependence of Conditional Temperature Structure Function --- p.72 / Chapter 6 --- Discussion --- p.78 / Chapter 6.1 --- Comparison with passive measurement --- p.78 / Chapter 6.2 --- Pr-dependence of Conditional PDF on XT --- p.87 / Chapter 7 --- Conclusion --- p.90 / Bibliography --- p.94
74

Statistics and coherent structures in turbulent convection =: 對流湍流中統計及相干結構的硏究. / 對流湍流中統計及相干結構的硏究 / Statistics and coherent structures in turbulent convection =: Dui liu tuan liu zhong tong ji ji xiang gan jie gou de yan jiu. / Dui liu tuan liu zhong tong ji ji xiang gan jie gou de yan jiu

January 1998 (has links)
by Ma Kin Lok. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 93-95). / Text in English; abstract also in Chinese. / by Ma Kin Lok. / Acknowledgements --- p.i / Abstract --- p.ii / Abstract (Chinese version) --- p.iv / Contents --- p.v / List of Figures --- p.vii / List of Tables --- p.ix / Chapter Chapter 1. --- Introduction --- p.1 / Chapter Chapter 2. --- Experimental setups and Coherent structures --- p.10 / Chapter 2.1 --- Experimental setup for turbulent convection using helium --- p.10 / Chapter 2.2 --- Experimental setup for turbulent convection using water --- p.12 / Chapter 2.3 --- Coherent structures in turbulent convection --- p.13 / Chapter Chapter 3. --- Statistics in turbulent convection --- p.16 / Chapter 3.1 --- Statistics versus Rayleigh number and height --- p.16 / Chapter 3.1.1 --- Time series of normalized temperature fluctuations --- p.17 / Chapter 3.1.2 --- PDF of normalized temperature fluctuations --- p.18 / Chapter 3.1.3 --- q(x) and r(x) --- p.21 / Chapter 3.2 --- Statistics versus height --- p.25 / Chapter 3.2.1 --- Time series of normalized temperature fluctuations --- p.25 / Chapter 3.2.2 --- PDF of normalized temperature fluctuations --- p.28 / Chapter 3.2.3 --- Skewness and flatness of normalized temperature fluctuations --- p.32 / Chapter 3.2.4 --- q(x) and r(x) --- p.33 / Chapter Chapter 4. --- Decomposition of the helium data --- p.40 / Chapter 4.1 --- Method of study for decomposition --- p.41 / Chapter 4.2 --- Effects of the decomposition on P(x) --- p.44 / Chapter 4.3 --- Modeling of coherent structures by average peaks --- p.46 / Chapter 4.4 --- The two conditional averages of the average peaks --- p.52 / Chapter 4.5 --- Effects of the peaks on PDF --- p.57 / Chapter Chapter 5. --- Statistics of Temperature Dissipation Rate --- p.62 / Chapter 5.1 --- She and Leveque's model for energy dissipation rate --- p.62 / Chapter 5.2 --- Limits of moments of temperature dissipation rate --- p.66 / Chapter 5.3 --- Scaling of moments of temperature dissipation rate --- p.68 / Chapter Chapter 6. --- Conclusions --- p.37 / Appendix A. The relation between Nu and λth --- p.89 / Appendix B. The algorithm of filtering the peaks --- p.90 / Appendix C. Effect of normalization on the conditional averages --- p.91 / Bibliography --- p.93
75

Turbulent thermal convection under modified boundary conditions: an experimental study of heat transport and boundary layers. / 改變邊界條件下的熱湍流對流系統: 傳熱性質及邊 界層的實驗研究 / CUHK electronic theses & dissertations collection / Turbulent thermal convection under modified boundary conditions: an experimental study of heat transport and boundary layers. / Gai bian bian jie tiao jian xia de re tuan liu dui liu xi tong: chuan re xing zhi ji bian jie ceng de shi yan yan jiu

January 2013 (has links)
本論文將詳述對湍流熱對流系統改變邊界條件的三組實驗。 / 第一組實驗中,在寬高比等於1 的圓柱形對流槽中,通過平滑板和由金字塔狀規則排列的粗糙表面的板的組合,我們對五個對流槽進行測量。对實驗測量得到Nu 和Ra 的关系式,进行两个指数函数关系式的叠加--分别是由GL 模型提出的主体主导的(1/2)指数和边界层主导的(1/4)指数关系式。两个关系式的系数之比表明,粗糙板可以提高主体的贡献,而且将系统从边界层主导转变到主体主导。而對各個板上的測量顯示,改變平板的條件,比如恒定熱量或者恒定溫度條件,以及同一個對流槽中另外一塊板是否粗糙板,該平板的傳熱沒有發生變化。而對於粗糙版,讓它處於恒定熱量或者恒定溫度條件,得到不同的結果;同一個槽中另外一塊板是平板或者粗糙板,該粗糙板的傳熱也會受影響。 / 第二組實驗中,在平滑板组成的对流槽,和两块粗糙板组成的对流槽中,我们添加高分子聚合物,进一步研究添加的效果。对于平滑板的对流槽,研究观察到热传递效率Nusselt 数在添加聚合物之后降低。而且,添加的聚合物越多,Nu 降低越多,在聚合物浓度大约120ppm 的时候,Nu 降低了接近12%,而且保持不变。而对于粗糙板组成的对流槽,当聚合物浓度大于120ppm 的时候,Nu 提高了大约4%。 / 第三組實驗,在两块平滑板组成的圆柱形对流槽中,我们也对底板边界层内的速度场进行了实验测量。结果表明,在倾斜角度小于1°的时候,速度边界层的厚度δ[subscript v]与雷诺数的指数关系,与理论给的平流边界层的结果接近。当倾斜角度比较大的时候,边界层厚度与雷诺数的指数随着角度减小。 在不同瑞利数下,同一个倾斜角度时,测量得到的水平速度剖面通过标准化后,得到的形状是一致不变的。而对于不同的角度,标准化的形状之间,是有区别的。 / In this thesis three sets of experiments of turbulent Rayleigh-Bénard convection with modified boundary conditions are presented. / The first set of measurements were made in cylindrical cells with aspect ratio one and with various combinations of smooth and rough plates in the form of regularly-arrayed pyramids. The experimental results suggest that the Nu - Ra relationship can be represented by the combination of two power laws, corresponding to the bulk dominant regime (exponent=1/2) and boundary layer dominant one (exponent=1/4) of the Grossmann-Lohse model. The behaviors of the coefficients of the two power laws suggest that the roughness of the plate can enhance the contribution of bulk and push the system to change from the boundary dominant state to bulk dominant state. A further examination of the individual plates reveal that the heat transport properties of smooth plates are insensitive to the surface and boundary conditions of the other plate of the same cell, whether smooth or rough, or whether under constant flux or constant temperature. The heat transport properties of the rough plates, on the other hand, appear to depend on surface and boundary conditions of the other plate of the same cell. / In the second set of experiments we study the effect of polymer additives in two Rayleigh-Bńard convection cells, one with smooth top and bottom plates and the other with rough top and bottom plates. For the cell with smooth plates, a reduction of the measured Nusselt number (Nu) was observed. Furthermore, the amount of Nu reduction increases with increasing polymer concentration (c), reaching ~12% for c = 120 ppm and an apparent level-off thereafter. For the cell with rough plates, however, an enhancement (~4%) of Nu was observed when the polymer concentration is greater than 120 ppm. / The third set of experiments investigates the properties of the velocity boundary layer in turbulent Rayleigh-Bénard convection in a cylindrical cell when it is tilted with respect to gravity. It is found that at small tilt angles (θ ≤ 1°), the measured viscous boundary layer thickness δ[subscript v] scales with the Reynolds number Re with an exponent close to that for a Prandtl-Blasius laminar boundary layer. For larger tilt angles, the scaling exponent of δ[subscript v] with Re decreases with θ. The normalized mean horizontal velocity profiles measured at the same tilt angle but with different Ra are found to have an invariant shape. But for different tilt angles, the shape of the normalized profiles is different. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Wei, Ping = 改變邊界條件下的熱湍流對流系統 : 傳熱性質及邊界層的實驗研究 / 韋萍. / "November 2012." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 148-158). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese. / Wei, Ping = Gai bian bian jie tiao jian xia de re tuan liu dui liu xi tong : chuan re xing zhi ji bian jie ceng de shi yan yan jiu / Wei Ping. / Table of Contents --- p.vii / List of Figures --- p.xxii / List of Tables --- p.xxiv / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background of Turbulence --- p.1 / Chapter 1.2 --- Rayleigh-Bénard convection system --- p.4 / Chapter 1.2.1 --- Physical picture --- p.4 / Chapter 1.2.2 --- Structure of Rayleigh-Bénard convection --- p.8 / Chapter 1.2.3 --- Previous investigation about Rayleigh-Bérnard Convection --- p.11 / Chapter 1.3 --- Motivation of the thesis --- p.15 / Chapter 1.4 --- Organization of this thesis --- p.17 / Chapter 2 --- Experimental apparatus and method --- p.18 / Chapter 2.1 --- Experimental apparatus --- p.18 / Chapter 2.1.1 --- The convection cell with smooth conducting plate --- p.18 / Chapter 2.1.2 --- The rough conducting plate --- p.20 / Chapter 2.2 --- Experimental techniques --- p.21 / Chapter 2.2.1 --- Temperature measurements --- p.21 / Chapter 2.2.2 --- Particle Image Velocimetry (PIV) --- p.23 / Chapter 2.3 --- Correction of heat flux measurment --- p.25 / Chapter 3 --- Convective Heat Transfer in Bulk- and Boundary-Dominated Regimes in Turbulent Thermal Convection --- p.28 / Chapter 3.1 --- Introduction --- p.29 / Chapter 3.2 --- Apparatus and experimental method --- p.31 / Chapter 3.3 --- Results and discussion --- p.34 / Chapter 3.3.1 --- Homogenity of temperature measurement over plate --- p.34 / Chapter 3.3.2 --- The heat transport measurement Nu --- p.40 / Chapter 3.3.3 --- Different heat transport behaviors over smooth and rough plates --- p.41 / Chapter 3.3.4 --- Fluctuations of local temperature --- p.47 / Chapter 3.3.5 --- Velocity and Reynolds number measurement --- p.48 / Chapter 3.3.6 --- Comparison with theoretical model and understanding . --- p.50 / Chapter 3.4 --- Summary --- p.52 / Chapter 4 --- Enhanced and Reduced Heat Transport in Turbulent Thermal Convection with Polymer Additives --- p.54 / Chapter 4.1 --- Introduction --- p.55 / Chapter 4.2 --- Experimental setup and methods --- p.58 / Chapter 4.2.1 --- The convection cell and experimental parameters --- p.58 / Chapter 4.2.2 --- Characterization of Polymer --- p.59 / Chapter 4.2.3 --- Measurement of the polymer solution viscosity --- p.62 / Chapter 4.3 --- Results --- p.65 / Chapter 4.3.1 --- The Nusselt number measurement --- p.65 / Chapter 4.3.2 --- Fluctuations of Nu and the local temperature --- p.72 / Chapter 4.3.3 --- Velocity and Reynolds number behavior --- p.83 / Chapter 4.4 --- Discussions --- p.90 / Chapter 4.5 --- Summary --- p.94 / Chapter 5 --- Viscous boundary layer properties in turbulent thermal convection in a cylindrical cell: the effect of cell tilting --- p.97 / Chapter 5.1 --- Introduction --- p.98 / Chapter 5.1.1 --- Boundary layer measurements in turbulent thermal convection --- p.98 / Chapter 5.1.2 --- Organization of the chapter --- p.102 / Chapter 5.2 --- Experimental apparatus --- p.103 / Chapter 5.2.1 --- Convection cell --- p.103 / Chapter 5.2.2 --- PIV measurement --- p.104 / Chapter 5.3 --- Results and discussion --- p.104 / Chapter 5.3.1 --- Temperature profile and fluid properties --- p.106 / Chapter 5.3.2 --- Velocity profiles and the Reynolds number scaling --- p.106 / Chapter 5.3.3 --- The viscous boundary layer and its scaling with Ra and Re --- p.114 / Chapter 5.3.4 --- Fluctuations and statistical properties of the velocity field in the boundary layer --- p.121 / Chapter 5.3.5 --- Properties of shear stresses and near-wall quantities --- p.125 / Chapter 5.3.6 --- Dynamical scaling and the shape of velocity profiles in the boundary layer --- p.130 / Chapter 5.4 --- Summary --- p.138 / Chapter 6 --- Conclusion --- p.141 / Chapter 6.1 --- Conclusion of our work --- p.141 / Chapter 6.1.1 --- Comparison of the thermal convection with modified plates --- p.142 / Chapter 6.1.2 --- The effect of polymer additives in smooth and rough cells --- p.143 / Chapter 6.1.3 --- Velocity field with tilting angles --- p.144 / Chapter 6.2 --- Perspectives for further investigation --- p.146 / Bibliography --- p.148
76

Experimental and theoretical study of convective instability in an enclosure.

Won, Kwang Jong January 1979 (has links)
Thesis (Sc.D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1979. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Vita. / Bibliography: leaves 274-279. / Sc.D.
77

Dynamics of the large-scale circulation in high prandtl number turbulent Rayleigh-Bénard convection. / 高普朗特數瑞利-伯納德對流中大尺度環流動力學特性研究 / Dynamics of the large-scale circulation in high prandtl number turbulent Rayleigh-Bénard convection. / Gao pu lang te shu Ruili-Bonade dui liu zhong da chi du huan liu dong li xue te xing yan jiu

January 2012 (has links)
自然界中存在很多的湍流熱對流現象。他們對於工業,科學與技術有著非常重要的影響。在本論文中我們利用多温度探头的技术研究了湍流熱對流的理想模型-湍流瑞利-伯納德對流中的大尺度環流在高普朗特數下的動力學特性。 / 實驗中,我们利用水和電子液體FC77 作為工作物質,獲得了普朗特數Pr 從5.3 到19.4. 瑞利數Ra 範圍8.3 × 10⁸ 2.94 × 10¹¹.我們用了一個寬高比Γ 為1 的圓柱形對流槽來研究大尺度環流的動力學特性。我們發現,在高普朗特數的時候,大尺度環流仍然是一個single roll. 這個與我們期望的是一樣的。大尺度環流的強度δ 的概率密度函數是一個高斯分佈。但是左邊的尾巴可以用一個指數函數來描述。我們也觀察到了大尺度環流傾向於呆在一個特定的角向位置。我們還發現,大尺度流動的角向運動具有擴散運動的特性。但是,用FC77 作為工作物質時,這個角向運動的擴散係數比用水作為工作物質時小兩個量級。實驗中測量到的雷諾數Re 和瑞利數Ra 之間的標度率與之前的實驗結果相符合。同時這個標度率也和Grossman-Lohse 模型的預測相符合。 / 大尺度流動豐富的動力學特性,比如說流動停止,流向反轉,扭轉還有平移振盪以及流動模式轉換,都可以在高普朗特數的時候觀察到。比較有趣的是我們發現流動停止在一個三維系統中既不依賴於Ra, 又不依賴於Pr. 這個結果和二維的瑞利-伯納德對流完全不同。 / Turbulent thermal convection is of tremendous importance to many areas of science, technology as well as the environment. In this thesis, the dynamics of the large-scale circulation (LSC) in turbulent Rayleigh-B´enard convection, which is an idealised model to study turbulent thermal convection problem, is investigated using the multi-thermal probe technique in the high Prandtl number Pr regime. / Using two kinds of working fluids, namely water and Fluorinert FC77, we achieved Pr from 5.3 to 19.4 and Rayleigh number Ra from 8.3×10⁸ to 2.94×10¹¹. The dynamics of the LSC is measured in an aspect ratio unity convection cell. It is found that the LSC in the high Pr regime is a single roll structure as expected. The probability distribution of the flow strength δ is a Gaussian distribution function with exponential tail to the left. The preferred orientation is also observed, which is revealed by the PDF of azimuthal orientation θ of the LSC. The azimuthal motion of the LSC is a diffusive process, which is the same as previous studies. However, we found that the diffusivity of the angular speed using FC77 as the working fluid is two orders smaller than using water as working fluid. The scaling of the measured Reynolds number Re number based on the oscillation frequency of the LSC with respect to Ra is in good agreement with previous experimental results and also Grossman-Lohse model prediction. / The abundant dynamical features of the LSC, such as cessations, flow reversals, torsional and sloshing oscillations and flow mode transitions are also observed in the high Pr regime. One surprising finding is that the cessation frequency of the LSC ,based on the statistics of the mid-height level of thermistors, is independent of both Ra and Pr, which is quite different from the (quasi) two-dimensional turbulent Rayleigh-B´enard convection. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Xie, Yichao = 高普朗特數瑞利-伯納德對流中大尺度環流動力學特性研究 / 謝毅超. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 53-57). / Abstracts also in Chinese. / Xie, Yichao = Gao pu lang te shu Ruili-Bonade dui liu zhong da chi du huan liu dong li xue te xing yan jiu / Xie Yichao. / Abstract --- p.ii / Acknowledgement --- p.iv / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Natural convection and Rayleigh-B´enard convection --- p.1 / Chapter 1.2 --- Governing equation and control parameters of RB Convection --- p.2 / Chapter 1.3 --- The large-scale circulation in turbulent RB convection --- p.4 / Chapter 1.4 --- Motivation and organisation of this thesis --- p.6 / Chapter 2 --- Experimental Setup and Measurement Techniques --- p.7 / Chapter 2.1 --- The convection cell --- p.7 / Chapter 2.1.1 --- The conduction plate and sidewall --- p.7 / Chapter 2.1.2 --- Cooling and heating system --- p.7 / Chapter 2.1.3 --- Level of the convection system --- p.7 / Chapter 2.2 --- The thermistor and it’s calibration --- p.9 / Chapter 2.3 --- Multi-thermal-probe technique --- p.10 / Chapter 2.4 --- Data analysis method --- p.12 / Chapter 2.4.1 --- Sinusoidal fitting method (SF method) --- p.12 / Chapter 2.4.2 --- Temperature extrema extraction method (TEE method) --- p.13 / Chapter 2.5 --- Physical properties of FC77 --- p.14 / Chapter 2.6 --- Other equipment --- p.15 / Chapter 3 --- Dynamics of LSC in high Pr turbulent RBC --- p.16 / Chapter 3.1 --- Background --- p.16 / Chapter 3.2 --- Experimental setup and data analyse method --- p.18 / Chapter 3.3 --- Results and discussion --- p.19 / Chapter 3.3.1 --- General features of the LSC --- p.19 / Chapter 3.3.2 --- Statistics of the angular speed --- p.23 / Chapter 3.3.3 --- Reynolds number Re --- p.30 / Chapter 3.3.4 --- Cessations, reversals and flow mode transitions --- p.34 / Chapter 3.3.5 --- Torsional and sloshing motions of the LSC --- p.42 / Chapter 3.4 --- Summary --- p.48 / Chapter 4 --- Conclusion and outlook --- p.51 / Chapter 4.1 --- Conclusion --- p.51 / Chapter 4.2 --- Outlook --- p.51 / Bibliography --- p.53
78

Experimental investigations of natural convection both in water and in mercury at extremely low Grashof numbers

You, Shuzhen January 2011 (has links)
Digitized by Kansas Correctional Industries
79

Relations between velocity and temperature fluctuations in turbulent convection. / 湍流對流中速度及溫度漲落量之關係 / Relations between velocity and temperature fluctuations in turbulent convection. / Tuan liu dui liu zhong su du ji wen du zhang luo liang zhi guan xi

January 2003 (has links)
Chui Ka Wing = 湍流對流中速度及溫度漲落量之關係 / 徐家榮. / Thesis submitted in: August 2002. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 77-78). / Text in English; abstracts in English and Chinese. / Chui Ka Wing = Tuan liu dui liu zhong su du ji wen du zhang luo liang zhi guan xi / Xu Jiarong. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- The Kolmogorov 1941 Theory (K41) --- p.3 / Chapter 1.3 --- She-Leveque hierarchical structure(SLHS) --- p.4 / Chapter 1.4 --- Rayleigh-Benard convection --- p.6 / Chapter 2 --- Velocity and temperature structure functions --- p.11 / Chapter 2.1 --- The velocity measurements --- p.11 / Chapter 2.2 --- The characteristic time scales --- p.14 / Chapter 2.3 --- The validity of GESS --- p.18 / Chapter 2.4 --- The validity of SLHS and the estimated values of β --- p.22 / Chapter 3 --- Relations implied by Bolgiano scaling --- p.27 / Chapter 4 --- Correlation between temperature and velocity differences --- p.51 / Chapter 4.1 --- The correlation coefficient --- p.51 / Chapter 4.2 --- Normalized conditional average --- p.53 / Chapter 5 --- Generalized scaling between velocity and temperature struc- ture functions --- p.60 / Chapter 5.1 --- Relations between p and p --- p.70 / Chapter 5.2 --- Relation between Δpv and Δp --- p.72 / Chapter 6 --- Summary --- p.75 / Bibliography --- p.77 / Chapter A --- Derivation of Eq. (1.11) and (1.12) --- p.79 / Chapter A.1 --- Derivation of Eq.(1.11) --- p.79 / Chapter A.2 --- Derivation of Eq.(1.12) --- p.80
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High Prandtl number turbulent convection over rough surfaces. / 在粗糙表面的高普朗特數湍流對流實驗 / High Prandtl number turbulent convection over rough surfaces. / Zai cu cao biao mian de gao Pulangte shu tuan liu dui liu shi yan

January 2004 (has links)
Chan Ho-Sun = 在粗糙表面的高普朗特數湍流對流實驗 / 陳浩新. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 69-72). / Text in English; abstracts in English and Chinese. / Chan Ho-Sun = Zai cu cao biao mian de gao Pulangte shu tuan liu dui liu shi yan / Chen Haoxin. / Abstract (in English) --- p.i / Abstract (in Chinese) --- p.ii / Acknowledgements --- p.iii / Table of Contents --- p.iv / List of Figures --- p.vi / List of Tables --- p.viii / Chapters / Chapter 1. --- Introduction --- p.1 / Chapter 2. --- Theories about the Convection --- p.7 / Chapter 2.1 --- Rayleigh-Benard convection --- p.7 / Chapter 2.2 --- The Convection Equations --- p.8 / Chapter 3. --- Setup of the Experimental Environment --- p.15 / Chapter 3.1 --- The Convection Cell --- p.15 / Chapter 3.2 --- Thermistors --- p.19 / Chapter 3.3 --- The Working Fluids --- p.22 / Chapter 3.4 --- Thermal Measurements --- p.27 / Chapter 3.5 --- Temperature Control Box --- p.28 / Chapter 4. --- Heat Transport Measurement --- p.29 / Chapter 4.1 --- Correction Procedures --- p.30 / Chapter 4.2 --- The Non-Boussinesq Effects --- p.33 / Chapter 4.3 --- Experiment Results --- p.41 / Chapter 4.3.1 --- Triethylene Glycol --- p.41 / Chapter 4.3.2 --- Dipropylene Glycol --- p.45 / Chapter 4.4 --- Discussion on the Results of Heat Transport --- p.50 / Chapter 4.5 --- Discussion on the Results of RMS Fluctuations --- p.60 / Chapter 4.6 --- The data set of pr =1400 --- p.63 / Chapter 5. --- Conclusion --- p.65 / References --- p.69

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