Complex Spatio-Temporal Dynamics in Convection of Fluids

9705410这是一个更新换代的项目，其目的是对扩展动力系统中的非线性、非平衡模式形成现象进行实验和数值研究。有人建议研究两个平行板之间的加压气体的热对流，这一系统已经成为更广泛类型的图案形成现象的范例。该程序将重点研究以下两个问题：(1)继续定量研究斜层Rayleigh-Benard对流在一定瑞利数和倾角范围内的分岔图。(2)对水平和倾斜情况下的时空混沌进行了详细的实验和数值研究。有关这项研究的详细信息，请访问http://www.milou.msc.cornell.edu.。%这是一个研究局部有序模式的更新项目，其中许多模式在自然界中都很丰富。从云街到风沙中的涟漪都是这样的例子。当随着时间的推移观察这些模式时，很明显它们在不断变化。我们称这种行为为时空混沌。本研究项目的目的是对热对流模式中的时空混沌进行实验和数值研究。当底部加热浅层流体，顶部冷却时，在一定温差以上，对流以对流辊的形式形成：热流体在底部上升，冷流体从顶部下降。为了实现一个有许多对流辊的系统，我们使用加压气体。我们利用数字成像和图像处理技术，以及利用最新的超级计算机技术进行大规模的数值研究，来研究这种模式的演变。***

9705410 Bodenschatz This is a renewal project, the aim of which is the experimental and numerical investigation of non-linear, non-equilibrium pattern- forming phenomena in extended dynamical systems. It is proposed to study the thermal convection of pressurized gases confined between two parallel plates, a system which has been a paradigm for a wider class of pattern forming phenomena. In particular the program will focus on the investigation of the following two topics: (1) The continued quantitative study of the bifurcation diagram of inclined layer Rayleigh-Benard convection over a range of Rayleigh numbers and inclination angles. (2) The detailed experimental and numerical investigations of Spatio- temporal chaos in horizontal and inclined situations. Details in the research can be found at http://www.milou.msc.cornell.edu. %%% This is a renewal project to study locally ordered patterns, many of which abound in nature. Examples are from cloud streets to ripples in the windblown sand. When observing these pattern over time it becomes obvious that they are constantly changing. We call this behavior spatio-temporal chaos. The aim of this research project is the experimental and numerical investigation of spatio-temporal chaos in patterns of thermal convection. When heating a shallow fluid layer at the bottom and cooling it at the top, above a certain temperature difference convection sets in form of convection rolls: hot fluid is rising at the bottom and cold fluid is descending from the top. To realize a system that has many convection rolls we are using pressurized gases. We investigate the pattern evolution by using digital imaging and image processing techniques and also large scale numerical investigations using the latest supercomputer technology. ***