multiUQ is a novel tool that simulates gas-liquid multiphase flows and quantifies uncertainty in results due to variability about fluid properties and initial/boundary conditions. The benefit over a typical deterministic solver is that inexact information, such as variability in fluid properties or flow rates, can be included to determine the affect on simulation solutions. It is common to deploy non-intrusive methods which utilize many solutions from a deterministic solver to generate a distribution of possible results. Contrarily, multiUQ uses an intrusive uncertainty quantification method wherein variables of interest are functions of space, time, and additional uncertainty dimensions. The intrusive solver is run once, giving a distribution of solutions as an output, as well as desired statistics. We use polynomial chaos to create the stochastic variables, which represent a distribution of values at each grid point. The stochastic variables are substituted into the incompressible Navier-Stokes equations, which govern the stochastic fluid dynamics. A stochastic level set is used to capture the distribution of interfaces that are present in an uncertain multiphase flow. multiUQ is written in Fortran and uses a message passing interface (MPI) for parallel operation. Given the many applications of multiphase flows, including open flows, hydraulics, fuel injection systems, and atomizing jets, there is a massive potential benefit to calculating uncertainty information about these flows in a cost-effective manner.

Program summary

Program Title: multiUQ

CPC Library link to program files: https://doi.org/10.17632/yp5pkd5x89.1

Developer's repository link: https://bitbucket.org/markowkes/multiuq

Licensing provisions: GPLv3

Programming language: Fortran 95/2003

Supplementary material: Wiki available at repository link.

Nature of problem: Performing uncertainty quantification on simulations of gas-liquid multiphase flows to understand the impact of input uncertainty on simulation results.

Solution method: This software utilizes an intrusive approach to uncertainty quantification of multiphase flows. Deterministic variables are expanded to include an added uncertainty domain by way of polynomial chaos. Stochastic Navier-Stokes govern the flow field in an incompressible one-fluid approach. Multiphase flows are created by coupling a stochastic level set and surface tension.

中文翻译：

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multiUQ：用于多相流不确定性量化的软件包

multiUQ 是一种新颖的工具，可模拟气液多相流并量化由于流体特性和初始/边界条件的可变性而导致的结果不确定性。与典型的确定性求解器相比，它的优势在于可以包含不准确的信息，例如流体特性或流速的可变性，以确定对模拟解决方案的影响。部署非侵入式方法是很常见的，这些方法利用来自确定性求解器的许多解决方案来生成可能结果的分布。相反，multiUQ 使用侵入式不确定性量化方法，其中感兴趣的变量是空间、时间和附加不确定性维度的函数. 侵入式求解器运行一次，给出解决方案的分布作为输出，以及所需的统计数据。我们使用多项式混沌来创建随机变量，这些变量代表每个网格点的值分布。随机变量被代入不可压缩的 Navier-Stokes 方程，该方程控制随机流体动力学。随机水平集用于捕获存在于不确定多相流中的界面分布。multiUQ 是用 Fortran 编写的并使用消息传递接口 (MPI) 进行并行操作。鉴于多相流的许多应用，包括开放流、液压、燃料喷射系统和雾化射流，以具有成本效益的方式计算有关这些流的不确定性信息具有巨大的潜在好处。

程序概要

项目名称： multiUQ

CPC 库程序文件链接： https : //doi.org/10.17632/yp5pkd5x89.1

开发者存储库链接： https : //bitbucket.org/markowkes/multiuq

许可条款： GPLv3

编程语言： Fortran 95/2003

补充材料：可在存储库链接中找到 Wiki。

问题性质：对气液多相流模拟进行不确定性量化，以了解输入不确定性对模拟结果的影响。

求解方法：该软件利用侵入式方法对多相流的不确定性进行量化。通过多项式混沌，确定性变量被扩展为包括一个附加的不确定域。随机 Navier-Stokes 以不可压缩的单流体方法控制流场。多相流是通过耦合随机水平集和表面张力产生的。