Adaptive Algorithm and Mesh Refinement

这是一个少数民族职业进步奖。这项研究针对的是用于电子元件小型化的制造技术问题。这些技术最近已被应用于微型机械部件的制造。使用这类组件的设备通常会在设计中包含气流。然而，传统的气体流动模拟方法在应用于小型化系统时并不准确。取而代之的是，人们必须进行跟踪单个气体分子运动的计算。进行追踪单个粒子的数值计算的一个主要困难是，即使在现代的超级计算机上，这些计算也非常耗时。如果整个设备很大，但包含的关键部件很小，情况尤其如此。例如，计算机磁盘驱动器相对较大(约为蚂蚁大小)，但支撑旋转盘片上方的读/写头的气流通过一个大约为百万分之一英寸宽(约为可见光波长)的间隙。其目标是通过将颗粒计算和传统的流体力学计算结合到一个混合计算机程序中，有效地模拟作为宏观设备一部分存在的微观流动。只有需要粒子描述的区域才使用粒子计算，而在较大的体积中，则求解压力、温度等方程。该程序的最终结果将是一个复合方案，它将允许解决无法用任何单一技术有效计算的流动问题。

This is a Minority Career Advancement Award. The research is directed toward the problem of manufacturing techniques used to miniaturize electronic components. These techniques have recently been applied to the construction of microscopic mechanical components. Devices using such components often include a gas flow as part of their design. However, the conventional methods for simulating gas flows are not accurate when applied to miniaturized systems. Instead one must perform calculations that track the motion of individual gas molecules. A major difficulty with performing numerical calculations that track individual particles is that they are extremely time-consuming, even on a modern supercomputer. This is especially true if the entire device is large but contains a crucial component that is small. For example, in a computer disk drive is relatively large (about the size of an ant) but the air flow that supports the read/write head above the spinning platter passes through a gap that is roughly one millionth of an inch wide (about the wavelength of visible light). The goal is to efficiently simulate microscopic flows that exist as part of a macroscopic device by combining particle calculations and traditional hydrodynamic computations into a hybrid computer program. Only the regions that require a particle description are calculated using particles while in the larger volume the equations for pressure, temperature, etc. are solved. The end result of this program will be a composite scheme that will permit the solution to flow problems that cannot be effectively computed by any single technique.