UNS: multiphase-UQ: Uncertainty Quantification Framework for Multiphase Flow Simulations

1511325（Owkes）该提案的目标是开发一种新的方法来量化气液多相流计算流体动力学（CFD）模拟的不确定性。尽管人们在开发更精确的数值模拟技术上花费了大量精力，但在模拟实际工程问题时，面对流体性质、边界和初始条件等不可避免的不确定性，计算结果的准确性这一重要问题尚未得到解决。建议建立在单相流的最新发展，以耦合不确定性量化和多相流数值技术，并创建一个严格的方法来测量输入不确定性的输出不确定性。具体地说，将开发一个表示具有相关不连续面的随机界面的框架。PI将结合界面捕获方法（水平集和流体体积）和侵入式不确定性量化技术，开发一种随机水平集方法来表示不连续的气液界面。该框架将适用于其他具有不连续的应用中的不确定性传播，例如固体力学中的裂纹扩展和流固相互作用，并将有可能改变工程师研究和预测这些系统的方式。多相流在加工和制造工业中的应用十分普遍。所提出的模拟可以应用于许多领域，因为无数的工程和环境流，包括燃料喷射、质子交换膜（PEM）燃料电池、核能发电、聚光太阳能发电厂、生物流和波浪能量收集装置都受到多相流的影响。在蒙大拿州立大学托管的一个专用网站将提供模拟参数和数据的中心访问点。在这个项目中开发的数字代码和结果将通过PI的网站和蒙大拿州立大学的图书馆传播，该图书馆提供开放获取的传播服务。

1511325(Owkes)The goal of the proposal is to develop a novel methodology to quantify the uncertainty of computational fluid dynamic (CFD) simulations of gas-liquid multiphase flows. While a lot of effort has been spent on developing more accurate numerical techniques for simulations, the important question of the accuracy of computational results in the face of unavoidable uncertainty about fluid properties, boundary and initial conditions, which is present when real life engineering problems are simulated, has not been addressed.It is proposed to build upon recent developments for single-phase flows in order to couple uncertainty quantification and multiphase flow numerical techniques and to create a rigorous methodology for measuring output uncertainties from input uncertainties. Specifically, a framework for representing a stochastic interface with associated discontinuities will be developed. The PI will couple an interface capturing methods (level set and Volume of Fluid) with intrusive Uncertainty Quantification techniques to develop a stochastic level set method to represent discontinuous gas-liquid interfaces. This framework will be applicable for propagating uncertainty in other applications with discontinuities such as crack propagation in solid mechanics and fluid-structure interactions and will have the potential to change the way engineers study and predict these systems. Applications of multiphase flow occur quite commonly in the process and manufacturing industry. The simulations proposed can have applications to many areas, since a myriad of engineering and environmental flows including fuel injection, proton exchange membrane (PEM) fuel cells, nuclear power generation, concentrating-solar plants, biological flows, and wave energy harvesting devices are affected by multiphase flows. A dedicated website hosted at Montana State University will provide a central access point to the simulation parameters and data. Numerical codes and results developed during this project will be disseminated through the PI's website and through the library at Montana State University which provides open-access dissemination services.