Collaborative Research: Structured Wakes Behind Oscillating Foils: Characterization, Control, and Cooperative Behavior

使用摆动翼片的能源收集有可能利用大型水动力(潮汐和河流)能源，并向滨水社区提供可再生和可持续的能源。与传统的旋转式水力涡轮机相比，振动翼对海洋动植物的危害更小，可以在更多的位置和更低的水速下运行。振动箔也可以放置在彼此很接近的位置，从而增加功率密度--可以从给定区域提取的总功率。然而，优化这种布置依赖于对相邻水翼之间相互作用的更好理解，特别是对结构尾迹形成、向下游平流以及影响相邻水翼性能的方式的了解。这一研究项目将解决这些问题，并导致开发能够帮助开发商业上可行的水动能系统的预测工具，利用实验和计算方法的紧密结合，将开发一个系统的框架，用于系统地描述和控制振荡翼之间的尾迹相互作用。主要目的是根据扑翼运动的运动学对涡旋的拓扑结构和对流路径进行分类。这些工具将在机器学习分类和回归模型的帮助下开发。一旦尾迹结构得到很好的预测，控制算法将被开发出来，涡翼相互作用将被描述为有益和有害的相互作用，以达到能量收集的目的。将结合二维直接数值模拟(DNS)和三维大涡模拟(LES)对单个和多个水翼进行模拟。一个计算机控制的三水翼系统，每个系统都配备了力和扭矩传感器，将用于大型开放水面水槽中，并使用粒子图像测速仪(PIV)进行非定常尾流速度测量。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Energy harvesting using oscillating foils has the potential to tap large hydrokinetic (tidal and riverine) energy resources and provide renewable and sustainable energy to water-front communities. Oscillating foils are less harmful to marine flora and fauna, can operate in many more locations and at lower water speeds than is possible for conventional rotary hydrokinetic turbines. Oscillating foils can also be placed in close proximity to each other, increasing the power density - the total power that can be extracted from a given area. However, optimizing this placement depends on improved understanding of the interactions between adjacent hydrofoils, and in particular, the way in which structured wakes form, advect downstream and impact the performance of a neighboring hydrofoil. This research project will address these issues, and lead to the development of predictive tools that can aid in the development of commercially feasible hydrokinetic energy systems, Using a tightly-integrated combination of experimental and computational approaches, a systematic framework will be developed for systematically characterizing and controlling the wake interactions between oscillating foils. The primary goal is to categorize vortex topology & convective paths based on the kinematics of the flapping motion. These tools will be developed with aid of machine learning classification and regression models. Once the wake structure is well-predicted, control algorithms will be developed, and the vortex-foil interactions will be characterized in terms of beneficial and detrimental interactions for the purpose of energy harvesting. Simulations of single and multiple hydrofoils will be performed using a combination of two-dimensional direct numerical simulation (DNS) and three-dimensional Large Eddy Simulations (LES). A computer-controlled three-hydrofoil system each equipped with force and torque sensors will be used in a large open surface water flume in conjunction with unsteady wake velocity surveys using Particle Image Velocimetry (PIV).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.