Turbulence on a Free Surface

这个研究项目是关于流体动力学的。 它由材料研究部的凝聚态物理计划和化学与运输系统部的流体动力学和水力学计划共同资助。 这是一个研究湍流在自由表面的一个封闭的身体的流体。 通过观察在空气/水界面处夹带的小颗粒的平面内、水平速度分量来检测流体运动或湍流。一个大的激光照射表面颗粒，这些颗粒被一个快速相机跟踪。 在表面和表面以下的点处，流动是不可压缩的;这意味着表面速度是可压缩的。 由于能量和涡量可以自由地与下面的流体交换，因此无法获得柯尔莫哥洛夫类型的量纲参数，因此必须转向计算机模拟来模拟运动。 一个令人感兴趣的现象是粒子倾向于聚集而不是分散。 这些观测结果与实际问题有关，如污染物在湍流海面上的扩散和生物有机体在空气/水界面上的生长速度。 教育部分完全侧重于本科生。 实验技术，这是计算机密集型，为物理专业，工程师，和那些有兴趣在模式识别问题提供了一个很好的培训基地。 他们将为一系列的职业生涯做好准备，工业和政府这个流体动力学湍流研究项目是在材料研究部门的凝聚态物理计划和化学和运输系统部门的流体动力学和水力学计划之间共同资助的。 当物体在空中或海上快速移动时，湍流总是会出现。了解湍流的复杂现象是必要的，以便改进天气预报，更好地科普风暴和污染泄漏等自然和人为灾害。这里的重点是漂浮在湍流水体上的小颗粒的运动。 这些“漂浮物”可以被认为是浮标、船只或漂浮污染物运动的替代物。 表面的湍流具有使漂浮物聚集在一起的不寻常的效果，而它们分散在散装海洋或空气中的其他地方。 这项研究是在实验室控制条件下进行的首批研究之一。 教育部分完全集中在本科生。 该研究利用尖端技术来跟踪粒子运动（高速摄像机和强大的新型固态激光器），为基础科学或工程专业的学生提供了一个很好的训练基地。

This research project deals with fluid dynamics. It is co-funded between the Condensed Matter Physics Program In the Division of Materials Research and the Fluid Dynamics and Hydraulics Program in the Division of Chemical and Transport Systems. It is a study of turbulence at the free surface of a closed body of fluid. The fluid motion or turbulence is detected by observing the in plane, horizontal velocity components of small particles entrained at the air/water interface. A large laser illuminates the surface particles, which are tracked with a fast camera. At points at and below the surface, the flow is incompressible; this implies that the surface velocity is, by contrast, compressible. Because energy and vorticity can be freely exchanged with the fluid below, Kolmogorov-type dimensional arguments are not available, so one must turn to computer simulations to model the motion. One phenomenon of interest is the tendency of particles to cluster rather than disperse. The observations are relevant to practical issues such as dispersal of pollutants at the surface of a turbulent sea and the growth rate of biological organisms at an air/water interface. The educational component is focused entirely on undergraduate students. The experimental techniques, which are computer intensive, provide an excellent training ground for physics majors, engineers, and those interested in pattern recognition issues. They will be prepared for a range of careers in academe, industry and governmentThis fluid dynamics turbulence research project is co-funded between the Condensed Matter Physics Program In the Division of Materials Research and the Fluid Dynamics and Hydraulics Program in the Division of Chemical and Transport Systems. Turbulence invariably appears when objects move rapidly through the air or the sea. An understanding of the complex phenomenon of turbulence is necessary in order to improve weather prediction and to better cope with natural and man-made disasters such as storms and pollution spills. The focus here is on the motion of small particles that float on a turbulent body of water. These 'floaters' may be thought of as a surrogate for the motion of buoys, ships, or floating pollutants. Turbulence at the surface has the unusual effect of causing the floaters to clump together, whereas they are dispersed elsewhere in the bulk sea or the air. This study is one of the first to be carried out under laboratory-controlled conditions. The educational component is focused entirely on undergraduate students. The research utilizes cutting-edge technology for tracking the particle motion (high-speed cameras and powerful new solid-state lasers) and provides an excellent training ground for students majoring in fundamental science or engineering.