Horizontal convection: the role of turbulence

智能优点：水平对流是沿着流体的一个水平边界进行差热而产生的循环的通用名称。这是海洋经向翻转环流的一个重要特征。子午线翻转环路的整个问题是复杂和困难的，涉及热、盐和机械作用力。理解更简单的(单组分)水平对流问题是解决完整问题的重要一步。混合对于产生一条冷水被修改并返回表面的路径至关重要。分子过程太微不足道，不能发挥这一作用。因此，湍流在水平对流中的作用是至关重要的。水平对流的实验室和数值实验将解决五个假设：1.以前工作中对边界层厚度的定标是正确的。2.耗散在空间上是高度可变的。3.定常和非定常区域之间的边界是纵横比、维度和旋转的函数。4.边界强迫的小尺度变化应使大尺度对流停止。5.浮力和机械强迫的组合改变了体制图。更广泛的影响：调查人员将从事多个层次的教育活动。首席研究员所在的环境流体动力学实验室在本科生指导方面有着良好的记录。他们将招收一名本科生，并将与加州大学圣地亚哥分校的麦克奈尔计划和/或科学研究暑期培训学院(STAR)计划合作，这两个计划的目标学生都来自传统上在科学界代表性较低的群体。这项研究将涉及两名研究生。接触到大学预科学生将有助于圣地亚哥联合学区高中教师的专业发展。他们将与国家科学基金会资助的加利福尼亚海洋科学教育卓越中心合作，为大约25名地球科学教师举办为期一天的讲习班。调查人员将在为这项工作选择的CFD代码的维基页面上做出贡献。这些帖子将在一个更大的CFD社区可以访问的场所广泛传播NSF资助的工作的关键成果，从而增进对科学和技术的理解。该项目的成果可应用于工业和环境可持续性，以及相关科学领域，特别是湖沼学和气候科学。这里进行的实验与建筑物的自然通风有关。提高对自然通风流体力学的理解是该项目的预期结果，可以为关键的节能努力提供信息，最终可能使社会在经济、环境和政治上受益。

Intellectual Merit: Horizontal convection is the generic designation for the circulation resulting from differential heating along one horizontal boundary of a fluid. It is a key feature of the ocean's Meridional Overturning Circulation. The full problem of the Meridional Overturning Circualtion is complex and difficult, involving thermal, haline, and mechanical forcing. Understanding the simpler problem of (single-component) horizontal convection is an important step in attacking the full problem. Mixing is critically important in producing a pathway for cold water to be modified and return to the surface. Molecular processes are far too puny to carry out this role. The role of turbulence in horizontal convection is hence crucial.The laboratory and numerical experiments on horizontal convection will address five hypotheses:1. Scaling for the boundary-layer thicknesses of previous work is correct. 2. Dissipation is highly variable in space. 3. The boundary between steady and unsteady regimes is a function of aspect ratio, dimensionality, and rotation. 4. Small-scale variability of the boundary forcing should shut down large-scale convection. 5. Combined buoyancy and mechanical forcing changes the regime diagram.Broader Impacts: The investigators will engage in educational activities at multiple levels. The environmental fluid dynamics laboratory, in which the lead investigator works, has a strong track record in undergraduate mentoring. They will recruit an undergraduate and will work with UCSD's McNair Program and/or the Summer Training Academy for Research in the Sciences (STARS) program, both of which target students are from groups traditionally underrepresented in the sciences. The research will involve two graduate students. Reaching pre-college students will contribute to the professional development of high school teachers in the San Diego Unified School District. In partnership with the NSF-funded Center for Ocean Science Education Excellence/California they will sponsor a one-day workshop for approximately 25 Earth sciences teachers. The investigators will contribute to the Wiki page of the CFD code chosen for this work. These posts will broadly disseminate key results of NSF-funded work in a venue that is accessed by the larger CFD community, thus enhancing scientific and technological understanding. The results of the project have applications in industry and to environmental sustainability, as well as in related fields of science, in particular limnology and climate science. The experiments carried out here are relevant to natural ventilation of buildings. Improved understanding of the fluid mechanics of natural ventilation, an anticipated outcome of the project, can inform critical energy conservation efforts that may ultimately benefit society economically, environmentally and politically.