Direct Numerical Simulation of Homogenous Turbulence for Planktonic Organisms

这项调查是全球海洋生态系统的一部分 动力学-美国全球陈纳格研究计划。 是 旨在量化浮游生物之间的相互关系 对流动力学和湍流。 这个项目源于这样一个事实 文献中假设， 种群动态仅取决于 捕食者和猎物生物，但越来越多的理论和 经验证据表明，湍流可以改变 接触率 使用超级计算机，湍流可以被模拟 直接从Navier-Stokes方程（DNS），因此模拟 字段是“真实的”流。 在一个尺度上的流动可视化 个体的非营养性有机体是教育我们的 科学头脑 累积海洋湍流测量 提供足够的信息来解释数值模拟 湍流就像海洋湍流一样。 对数正态概率 密度函数将被用来模拟统计数据， 湍流围绕着一个无张力的有机体。 将开发一个计算机程序来减少 DNS所需的计算。 该计划将创建一个 高雷诺数下运动学修正无规流场 这是一个无法从DNS获得的数字。 数据库将 为以后使用的模拟流场建立。 一 这个数据库的潜在用途将是测试 食物/摄入信号。 将采用随机模型来模拟 寄生生物。 目前随机游走是唯一的模型 然而，在拉格朗日模拟中，生物体显示出许多 更复杂的游泳行为。 一种改进的自回归模型 将为此目的进行调整。

This investigation is part of GLOBEC - Global Ocean Ecosystems Dynamics - of the U.S. Global Chenage Research Program. It is aimed at quantification of the interrelation between plankton trophodynamics and turbulence. This project stems form the fact that the literature assumes that trophodynamics and consequent population dynamics depend only on the relative density of predator and prey organisms, yet growing theoretical and empirical evidence indicates that turbulence can be alter the contact rate. Using a supercomputer, turbulence can be simulated directly from the Navier-Stokes equation (DNS) so the simulated field is a "real" flow. Flow visualization at the scale of an individual planktonic organism is the best way to educate our scientific mind. Accumulated oceanic turbulence measurements provide enough information to interpret the numerically simulated turbulence as oceanic turbulent flow. A lognormal probability density function will be used to model the statistics of turbulent flow around a planktonic organism. A computer program will be developed to reduce the amount of computation required for DNS. This program will create a kinematically correct random flow field at a high Reynolds number, which is unavailable from DNS. A data base will be established for the simulated flow field for later uses. A potential use of this data base will be to test the notion of food/ingestion signals. A stochastic model will be employed to model the behavior of a planktonic organism. Currently random walk is the only model used in Lagrangian simulations, however, the organism shows much more complex swimming behavior. A modified Auto-Regressive model will be adapted for this purpose.