CAREER: Unsteady inertial dynamics of suspensions: transport, assembly and propulsion

控制悬浮在液体中的微观颗粒的运动在各种技术应用中都很重要，包括操纵医疗和分析设备中的细胞，将颗粒组装成结构和特殊材料，以及开发自推进颗粒。这一职业奖将支持开发新的模拟方法，以预测和控制由悬架快速振荡驱动的粒子运动。该项目将模拟单个粒子、成对的粒子，并最终模拟粒子的组合，考虑粒子之间的相互作用影响其运动的方式。一系列针对K-12、本科生和研究生的教育活动，特别是那些来自代表性不足群体的学生，将被纳入该项目。研究中遇到的原理演示将通过Ameal Moore自然中心向公众传播，高中生将通过实践项目参与，这些项目将整合到教师培训模块中。这个职业项目的目标是发展对时间周期驱动的颗粒物悬浮的运输、组装和推进的基本理解。这将通过渐近理论、粒子动力学模拟和实验室实验来实现。研究人员将首先建立振荡流动下颗粒悬浮动力学的非线性理论框架，引用快慢时间尺度的分离，并考虑粘性惯性流体动力相互作用。实验室实验将研究振动悬浮物如何在约束下组装成平面和三维结构。装配动力学和由此产生的结构将使用粒子模拟进行解释。最后，研究人员将使用理论和计算技术来研究惯性在自我推进中的作用，在自我推进中，振荡流是由游泳者身体的波动所激发的。因此，该项目将确定和量化在振荡激励下控制被动和主动颗粒悬浮液流动的机制。该项目的基础科学进展及其潜在的应用有望激发新的颗粒组装控制策略，并促进对惯性颗粒流的进一步研究。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。

Controlling the movement of microscopic particles suspended in a liquid is important in a variety of technical applications, including the manipulation of cells in medical and analytical devices, the assembly of particles into structures and specialized materials, and the development of self-propelled particles. This CAREER award will support development of new simulation methods to predict and control particle motion that is driven by rapid oscillations of the suspension. The project will simulate individual particles, pairs of particles and, ultimately, assemblies of particles, taking into account the way interactions among the particles influence their motion. An array of educational activities aimed at K-12, undergraduate and graduate students, especially those from underrepresented groups, will be integrated into the project. Demonstrations of principles encountered in the research will be disseminated to the public through the Ameal Moore Nature Center, and high-school students will participate through hands-on projects that are integrated into training modules for teachers.The goal of this CAREER project is to develop a fundamental understanding of transport, assembly and propulsion in time-periodically driven particulate suspensions. This will be achieved using asymptotic theory, particle-dynamics simulations, and laboratory experiments. The investigators will first develop a nonlinear theoretical framework for particulate suspension dynamics under oscillatory flow, by invoking the separation between fast and slow timescales, and accounting for visco-inertial hydrodynamic interactions. Laboratory experiments will study how vibrated suspensions assemble into planar and three-dimensional structures under confinement. The assembly dynamics and the resulting structures will be interpreted using particle simulations. Finally, the researchers will use theoretical and computational techniques to investigate the role of inertia in self-propulsion, where oscillatory flow is excited by undulations of the body of the swimmer. Thus, the project will identify and quantify the mechanisms controlling the flow of passive and active particulate suspensions under oscillatory excitation. The fundamental scientific advances of the project and its potential applications are expected to inspire new control strategies for particle assembly and prompt further research on inertial particulate flows.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.