Complex fluids in the animal kingdom

Tradeoffs between energy efficiency and mechanical response in fluid flow networks

Transport networks are typically optimized, either by evolutionary pressures in biological systems or by human design in engineered structures. In the case of systems such as the animal vasculature, the transport of fluids is hindered by the inherent viscous resistance to flow while being kept in a dynamic state by the pulsatile nature of the heart and elastic properties of the vessel walls. While this imparted pulsatility necessarily increases the dissipation of energy caused by the resistance, the vessel elasticity helps to reduce overall dissipation by attenuating the amplitude of the pulsa…

弹涂鱼利用尾部推力辅助拐杖式运动，在不同湿度的泥地上移动

Mudskippers use tail thrusting to help crutching to move on mud of various wetness

本研究探究弹涂鱼在不同湿度泥地的运动，发现其主要采用拐杖式步态，湿度过高时辅以尾部推力，尾部使用是其运动适应的主要创新点。

Oscillatory fluid flow drives scaling of contraction wave with system size

Flows over remarkably long distances are crucial to the functioning of many organisms, across all kingdoms of life. Coordinated flows are fundamental to power deformations, required for migration or development, or to spread resources and signals. A ubiquitous mechanism to generate flows, particularly prominent in animals and amoeba, is acto-myosin cortex driven mechanical deformations that pump the fluid enclosed by the cortex. Yet, it is unclear how cortex dynamics can self-organize to give rise to coordinated flows across the largely varying scales of biological systems. Here, we develop a …

受限活性极性薄膜中的密度–极性耦合：星状体、螺旋体与双相取向相

Density-polarity coupling in confined active polar films: asters, spirals, and biphasic orientational phases

针对受限圆盘内活性极性流体，本文研究 +1 拓扑缺陷下密度与极性有序的耦合，揭示密度控制的螺旋体–星状体转变及双相取向相。

自然界中的流体喷射

Fluid ejections in nature

本文综述不同生物尺度上的主动与被动流体喷射，提出基于无量纲数的滴落—射流转变分析框架，并指出其生物物理意义及仿生工程应用。

SPIM-Flow：用于研究 Hydra 流体动力学的集成光片与微流控平台

SPIM-Flow, an integrated light-sheet and microfluidics platform for hydrodynamic studies of Hydra

开发了低成本光片平台SPIM-Flow，实现与微流控的简易集成，成功用于研究自由移动的 Hydra 的流体动力学及其对流动的响应行为。

海绵领细胞室的结构最大化机械泵送效率

The Architecture of Sponge Choanocyte Chambers Maximizes Mechanical Pumping Efficiency

该研究通过活体成像与多鞭毛计算模型揭示海绵领细胞室的球形结构及逆流鞭毛通过提升腔内压力使机械泵送效率在特定出口张角下最大化，并发现多个物种的结构参数均符合该优化关系。

Simulating cilia-driven mixing and transport in complex geometries

Cilia and flagella are self-actuated microtubule-based structures that are present on many cell surfaces, ranging from the outer surface of single-cell organisms to the internal epithelial surfaces in larger animals. A fast and robust numerical method that simulates the coupled hydrodynamics of cilia and the constituent particles in the fluid such as rigid particles, drops or cells would be useful to not only understand several disease and developmental pathologies due to ciliary dysfunction but also to design microfluidic chips with ciliated cultures for some targeted functionality---e.g., ma…

纤毛节律波在管中的流变流体运动

Rheological fluid motion in tube by metachronal wave of cilia

本文理论研究了纤毛节律波驱动轴对称管中幂律流变流体的输运，发现流量依赖纤毛长度，且在特定条件下接近人类输出小管的估计值，泵送随流体增稠而改善。

Emergent Flows, Irreversibility and Unsteady Effects in Asymmetric and Looped Geometries

Fluid transport networks are important in many natural settings and engineering applications, from animal cardiovascular and respiratory systems to plant vasculature to plumbing networks and chemical plants. Understanding how network topology, connectivity, internal boundaries and other geometrical aspects affect the global flow state is a challenging problem that depends on complex fluid properties characterized by different length and time scales. The study of flow in micro-scale networks focuses on low Reynolds numbers where small volumes of fluids move at slow speeds. The flow physics at t…

将飞行编队建模为流动介导物质

Modeling flying formations as flow-mediated matter

本研究提出将飞行编队视为流动介导物质的模型，基于修正的空气动力学模型复现了扑翼箔片相互作用实验，揭示了群体的软晶体特性、波传播与不稳定性机制，为理解动物集体行为提供了新类比视角。