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UNSflow: A low-order, open-source solver for problems that involve unsteady and nonlinear fluid dynamics

UNSflow：一个低阶开源求解器，用于解决涉及不稳定和非线性流体动力学的问题

基本信息

批准号：
EP/R008035/1
负责人：
Kiran Kumar Ramesh
金额：
$ 12.84万
依托单位：
University of Glasgow
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2018
资助国家：
英国
起止时间：
2018 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FR008035%2F1
关键词：
UNSflow low order open source

项目摘要

This project aims to derive and develop new theoretical and low-cost numerical methods for analysing general unsteady aerofoil and wing flows that may exhibit nonlinearities such as flow separation and vortex shedding. The solvers implemented through these methods will be made available (open-source) to the public, academia and industry through the UNSflow project. Unsteady fluid dynamics is ubiquitous in modern aerospace research problems such as aerodynamic optimisation of wind-energy harvesting devices, design of flapping wing fliers, use of flapping foils for propulsion/high-lift, and design of aircraft with flexible wings (such as HALE - High-Altitude Long Endurance, or futuristic aircraft with large aspect ratios). Reducing emissions of pollutants and greenhouse gases, which is the prime motivation behind many of these problems, can only be accomplished by a mix of renewable strategies and incremental improvements. The flow physics in these problems exhibits significant nonlinearities arising from flow separation and vortex shedding which cannot be adequately represented by closed-form theoretical formulations. Though computational fluid dynamics (CFD) and experimental methods have contributed much to the understanding of unsteady flow features, they are unsuitable for use in preliminary design and optimisation because of time and cost considerations. This project aims to develop low-cost, physics-based models for unsteady aerodynamics based on the discrete-vortex method, which will enable fast simulations of medium-fidelity, and provide a simple framework for parametric studies, design optimisation, real-time simulation and interdisciplinary studies (by coupling with other solvers). UNSflow intends to be a new class of low-cost solvers that sacrifice an acceptable level of accuracy in fluid simulations for a tremendous speedup in simulation time, while being fully physics-based and retaining the fundamental flow quantities. The guiding philosophy in development of the solver is to retain only the physics which are significant in the flow regimes of specific applications. They are hence not an alternative to high-fidelity CFD and experiments, which will still be needed in the final phases of industrial production, but for fewer ideas/concepts. In effect, this will lead to reduced time and cost in the design cycle, and perhaps even a better solution in the long run, because more exploration of the design space will be possible. This research also intends to support the activities of teachers, students and hobbyists who may not have access to CFD software and computing resources. Potential applications for this class of users include design of ornithopters, quadcopters, and home-made wind-energy harvesting devices.The research to be carried out in this project is fundamental in nature and underpins several applied problems. It is intended to derive new theoretical and numerical tools to study general unsteady flows with intermittent separation and reattachment. It will assist the principal investigator's research group in its research on applied problems such as aerodynamic optimisation, dynamic stall alleviation, flapping-wing design and wind-energy harvesting. The research will also be useful to other research groups working on unsteady flows (for both fundamental and applied research), as a preliminary design/analysis tool for various applications, and student projects.

本项目旨在推导和发展新的理论和低成本的数值方法来分析可能表现出非线性的翼型和机翼流动，如流动分离和旋涡脱落。通过这些方法实现的求解器将通过UNSflow项目向公众、学术界和工业界提供（开源）。非定常流体动力学在现代航空航天研究问题中无处不在，如风能收集装置的气动优化、扑翼飞行器的设计、使用扑翼推进/高升力、柔性机翼飞机的设计（如HALE -高空长航时或大展弦比的未来飞机）。减少污染物和温室气体的排放，这是许多问题背后的主要动机，只能通过可再生战略和渐进式改进相结合来实现。这些问题中的流动物理表现出由流动分离和旋涡脱落引起的显著非线性，这种非线性不能用封闭形式的理论公式充分表示。尽管计算流体动力学（CFD）和实验方法对非定常流动特性的理解做出了很大贡献，但由于时间和成本的考虑，它们不适合用于初步设计和优化。该项目旨在开发基于离散涡方法的低成本、基于物理的非定常空气动力学模型，这将实现中等保真度的快速模拟，并为参数研究、设计优化、实时仿真和跨学科研究（通过与其他求解器耦合）提供一个简单的框架。UNSflow旨在成为一种新型的低成本求解器，它在流体模拟中牺牲了可接受的精度水平，以极大地加快模拟时间，同时完全基于物理并保留基本流量。求解器开发的指导思想是只保留在特定应用的流态中有意义的物理。因此，它们不是高保真CFD和实验的替代品，它们在工业生产的最后阶段仍然需要，但用于较少的想法/概念。实际上，这将减少设计周期中的时间和成本，从长远来看甚至可能是更好的解决方案，因为对设计空间的更多探索将成为可能。本研究还旨在支持教师、学生和业余爱好者的活动，他们可能无法获得CFD软件和计算资源。这类用户的潜在应用包括设计扑翼机、四轴飞行器和自制风能收集设备。在这个项目中进行的研究在本质上是基础性的，是几个应用问题的基础。旨在推导新的理论和数值工具来研究具有间歇分离和再附着的一般非定常流。它将协助首席研究员的研究小组进行应用问题的研究，如空气动力学优化、动态失速缓解、扑翼设计和风能收集。这项研究也将对其他从事非定常流研究的研究小组有用（无论是基础研究还是应用研究），作为各种应用和学生项目的初步设计/分析工具。