Deformation of porous flexible strip in low and moderate Reynolds number flows
Deformation of porous flexible strip in low and moderate Reynolds number flows
复制标题
多孔柔性带在低雷诺数和中雷诺数流动中的变形
作者：
M. Pezzulla;E. Strong;F. Gallaire;P. Reis
我们给出了悬臂式多孔柔性带材流固耦合的实验和数值研究结果。我们描述了条带的稳态变形及其相关的阻力，重点是低和中等雷诺数(Re)区域。我们的微细加工条提供对孔隙率和渗透率的独立控制，这是以前研究中没有的功能。我们制造具有不同渗透率水平的条带，跨度超过两个数量级，同时将其孔隙率固定在50%。然后，垂直夹紧的多孔带被拖入粘稠的浴缸中。在实验的同时，我们通过局部阻力系数，将条带模拟为受低(或中等)雷诺力局部加载的弹性条带。在低Re时，我们发现垂直流动下刚性条带的Stokes模拟得到的阻力系数随渗透率变化小于10%。相反，在中等雷诺数时，阻力系数显著且非单调地依赖于渗透率。虽然孔隙率决定了低Re时的阻力系数，但我们的结果表明，在中等Re时，精确设计的渗透率起着主要作用，使阻力系数在设定的孔隙度水平上有很大的变化。由于孔隙率通过有效固体的密度与重量直接相关，因此了解固定孔隙率和不同渗透率的多孔结构如何与周围流体相互作用对于飞行昆虫和微型无人机具有重要意义。
We present results from a combined experimental and numerical investigation of the fluid-structure interaction of cantilevered porous flexible strips, towed through a fluid bath. We characterize the steady-state deformation of the strips and their associated drag, focusing on the low and moderate Reynolds (Re) number regimes. Our microfabricated strips offer independent control over porosity and permeability, a feature not available in previous studies. We fabricate strips with different levels of permeability, spanning over two orders of magnitude, while fixing their porosity at 50%. Then, the vertically clamped porous strips are towed inside a viscous bath. In parallel to the experiments, we model the strip as an elastica that is loaded locally by low (or moderate) Reynolds forces, via local drag coefficients. At low Re, we find that the drag coefficient, which can be obtained from Stokes simulations of rigid strips under perpendicular flow, varies with permeability by less than 10%. By contrast, at moderate Re, the drag coefficient depends significantly and nonmonotonically on permeability. Whereas porosity dictates the drag coefficient at low Re, our results demonstrate that a precisely designed permeability plays a major role at moderate Re, enabling large variations of the drag coefficients at a set level of porosity. Since porosity is directly linked to weight via the density of the effective solid, understanding how porous structures of fixed porosity and varying permeability interact with the surrounding fluid is of relevance to flying insects and microdrones.
影响因子：
3.7
作者：
K. Steiros;M. Hultmark
通讯作者：
K. Steiros;M. Hultmark
影响因子：
64.8
作者：
Jafferis, Noah T.;Helbling, E. Farrell;Wood, Robert J.
通讯作者：
Wood, Robert J.