Experimental Environmental Hydraulics: Turbulent Entrainment and Mixing

实验环境水力学：湍流夹带和混合

• 批准号: RGPIN-2022-03438
• 负责人: Gaskin, Susan
• 金额: $ 3.13万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=749501
• 关键词: Experimental; Environmental; Hydraulics; Turbulent; Entrainment

Water is not only essential for life and the environment, but also for a functioning infrastructure for society's use. Solutions for the anthropogenic use of water and its impact on surface water resources (lakes, rivers, oceans) are investigated and developed in environmental hydraulics and in water resources engineering. Three problems are addressed in this proposal i) improving pollutant dispersion modelling in surface water, ii) prediction of fluvial erosion of cohesive sediments and iii) assessing and treating metal contamination of drinking water. For applied problems of pollutant dispersion in the hydrosphere, an understanding of the fundamental fluid dynamics of turbulent mixing is required. Two cases in which current dispersion models overestimate dilution are considered. Firstly, momentum jets carrying pollutants are released into turbulent flows in lakes, rivers and oceans, yet the dispersion is currently modelled based on the expedient assumption that the dilution due to turbulent diffusion can be added to the jet driven dilution. Recently it has been shown that, in fact, dilution is reduced in this case, motivating a fundamental study of the change in entrainment for a jet in a turbulent ambient. Second, the mixing downstream of river confluences can result in two streams flowing side by side for up to a hundred kilometers. The fluid mechanics of the mixing layer between the coflowing streams will be studied to understand, and then predict, the reduced transverse mixing occurring in these shallow flows. In water resources engineering, river engineers are finding unexpected river bank erosion in cohesive sediments (clays and tills) caused by higher and more variable river flows occurring due to urbanisation and higher intensity precipitation events due to climate change. As the fluvial erosion mechanisms and thresholds vary as a function of the character and depositional history of the sediment, a field survey will be undertaken to sample a representative number of cohesive sediment samples in the Great Lakes and St. Lawrence Lowlands. The samples will be subject to fluvial erosion tests and geotechnical tests will characterize the sediments allowing the range of behaviours to be classified in order to better predict erosion risk. The provision of an adequate quantity and an adequate quality of drinking water is required to ensure public health. Metal contamination of drinking water is a concern due to it neurotoxicant effect. While the neuro-toxicity of arsenic is well known, copper, although a micronutrient, has recently been linked to Alzheimer's disease. This motivates the development of a cheap point-of-use treatment for arsenic in water using waste shells as the active ingredient, and an investigation of exposure to copper from drinking water and a detailed review of drinking water guidelines.

水不仅对生命和环境至关重要，而且对供社会使用的正常运作的基础设施也至关重要。在环境水力学和水资源工程中，研究和开发人类用水及其对地表水资源（湖泊，河流，海洋）影响的解决方案。该提案涉及三个问题：一）改进地表水污染物扩散模型;二）粘性沉积物河流侵蚀预测;三）评估和处理饮用水金属污染。对于水圈中污染物扩散的应用问题，需要了解湍流混合的基本流体动力学。两种情况下，目前的分散模型高估稀释被认为是。首先，携带污染物的动量射流被释放到湖泊、河流和海洋中的湍流中，然而目前的扩散是基于这样的权宜假设来建模的：由于湍流扩散而导致的稀释可以被添加到射流驱动的稀释中。最近，它已被证明，事实上，在这种情况下，稀释减少，激励在湍流环境中的射流卷吸的变化的基础研究。其次，河流汇合处下游的混合可以导致两条河流并排流动长达一百公里。将研究同向流之间的混合层的流体力学，以了解，然后预测，减少横向混合发生在这些浅流。在水资源工程中，河流工程师发现粘性沉积物（粘土和冰碛物）中意外的河岸侵蚀，这是由于城市化和气候变化导致的更高强度降水事件导致的更高和更多变的河流流量造成的。由于河流侵蚀机制和阈值随沉积物的性质和沉积历史而变化，因此将进行实地调查，在五大湖和圣劳伦斯低地采集具有代表性的粘性沉积物样本。将对样品进行河流侵蚀试验，并通过土工试验确定沉积物的特性，以便对各种特性进行分类，从而更好地预测侵蚀风险。为确保公众健康，需要提供充足数量和质量的饮用水。饮用水中的金属污染是一个令人关注的问题，因为它具有神经毒性作用。虽然砷的神经毒性是众所周知的，但铜虽然是一种微量营养素，但最近与阿尔茨海默病有关。这促使开发一种利用废贝壳作为活性成分的廉价使用点处理水中砷的方法，并对饮用水中铜的暴露情况进行调查，并详细审查饮用水准则。