Numerical & Experimental Studies in Developing Turbulent Flows Via Multi-Scale Similarity

该项目旨在对复杂流动进行数值模拟，以更好地理解在不同雷诺数下，湍流如何在光滑/粗糙表面上发展。pi计划整合理论、实验和计算大涡模拟（LES）和直接Navier-Stokes （DNS）计算，以增加对压力梯度流动的理解。主要目的是通过多尺度相似度方法证明LES/DNS方法对强逆压梯度（APG）流动的适用性。如果成功，这将是LES技术首次应用于中等雷诺数的APG流动。利用LDA进行光滑和粗糙表面实验，验证数值解的正确性。PI的多尺度相似度方法是一种改进，因为它对内外流使用了不同的尺度。Lund等人（1998）为零压力梯度流动开发的重标度方法首次适用于APG，尽管单一标度方法失败。pi寻求开发分析工具来计算表面摩擦定律和粗糙边界层的分离准则。这项研究将由伦斯勒纳米技术创新计算中心催化，这是一台70 TFLOP的超级计算机，可以为湍流社区进行最广泛的模拟之一。实验将在配备独特光学仪器和低湍流强度（小于0.1%）的新边界层风洞设施进行。本文提出的研究是为两名来自代表性不足群体的学生设计的，他们将全职投入到这个项目中。在这个项目中，为学生提供的一些额外的拓展活动将包括为本科生提供参与研究的经验，为参与的博士后和本科生提供一对一的指导，并为参与的学生举办多尺度、数据分析和并行计算的暑期讲习班。该项目将对接并使用RPI现有的教授研究生教育联盟（AGEP）基础设施和专业知识。例如，研讨会和夏季讲习班将被记录下来并上传到网站上。这将有助宣传及招收学生。该奖项也由海军研究办公室（R. Joslin PD）资助。

CBET-0829020CastilloThis project seeks to perform numerical simulations of complex flows subject to adverse pressure gradient with eventual separation to better understand how the turbulent flows develop over smooth/rough surfaces at different Reynolds numbers. The PIs plan the integration of theoretical, experimental and computational Large Eddy Simulation (LES) and Direct Navier-Stokes (DNS) computations to increase the understanding of pressure gradient flows. The main objective is to demonstrate the suitability of LES/DNS methods to strong adverse pressure gradient (APG) flows with eventual separation by using the multi-scale similarity method. If successful, this will be the first time that the LES technique works on APG flows at moderate Reynolds numbers. Validation of the numerical solution will be confirmed with the smooth and rough surface experiments carried out by means of LDA. The PI's multi-scale similarity method is an improvement because it uses different scales for the inner and outer flow. For the first time the rescaling method developed by Lund et al. (1998) for zero pressure gradient flows works on APG, although the single scaling approach fails. The PIs seek to developed analytical tools to calculate the skin friction law and a separation criterion for rough boundary layers. This research will be catalyzed by the Rensselaer's Computational Center for Nanotechnology Innovations, a 70 TFLOP supercomputer, to carry out one of the most extensive simulations available for the turbulence community. Experiments will be carried out at the new Boundary Layer Wind Tunnel Facility equipped with unique optical instrumentation and low turbulence intensity (less than 0.1%). The research proposed herein has been designed for two students from underrepresented groups to dedicate full time to this project. Some additional outreach activities for students in the proposed project will include engaging research experiences for undergraduate students, providing one-to-one mentoring for the participant postdoctoral fellow and undergraduate students, and having summer workshops on multi-scales, data analysis and parallel computing for participating students. The project will interface and use the existing Alliances for Graduate Education in the Professoriate (AGEP) infrastructure and know-how at RPI. For example, seminars and summer workshops will be recorded and uploaded on a website. This will facilitate dissemination and student recruitment. This award is also funded at the Office of Naval Research (R. Joslin PD).