The N.E.O.N.-Bridge is a capstone project being developed by students at TAMUCC, under the oversight of Los Alamos National Laboratory. The project requires the development of a hull geometry for an autonomous bridge segment optimized to support onboard electronics and camera systems while maintaining stability in a dynamic water environment. Traditional ribbon bridge systems typically do not experience intense hydrodynamic loading due to current transportation and assembly methods, whereas the N.E.O.N-Bridge must continuously withstand forces from dynamic flow patterns. The requirement for a hull geometry to have both hydrodynamic design and rigidity, as in current ribbon bridges, has posed unique challenges. The current hull designs were evaluated through turbulent water-flow simulations performed with ANSYS Discovery. Boundary conditions were determined based on the forward motion of the bridge segment, simulating inlet and outlet flows, and the resulting pressure distribution. A waterline-based geometric constraint derived from the camera system's elevation enabled the simulation to model flow characteristics in an operational scenario. Velocity fields, pressure contours, and turbulent flow patterns were analyzed to identify areas of high loading and hydrodynamic inefficiencies. The findings will provide essential performance metrics that could be used to make design adjustments to the overall hull geometry. The simulation results will support improvements in stability, structural rigidity, and overall effectiveness of the hull geometry, advancing the development of the N.E.O.N-Bridge segments.
On the self-similarity of line segments in decaying homogeneous isotropic turbulence
CORIA – CNRS UMR 6614（CORIA – 法国国家科学研究中心 UMR 6614）；UM-SJTU Joint Institute, Shanghai JiaoTong University（上海交通大学上海交大大密西根学院）；Juelich Supercomputing Center（于利希超级计算中心）；RWTH Aachen University（亚琛工业大学）
本文用线段法研究了均匀各向同性衰减湍流中被动标量的自相似性。Gauding等人，Physics of Fluids 27.9（2015）：095102）。分析是基于一个高分辨率的衰减湍流直接数值模拟。直线段的方法被用来执行的标量场分解成更小的子单元的基础上的标量沿直线的极值点。这些子单元（所谓的线段）通过它们的长度$\ell$和端点之间的标量场的差$Δϕ$来参数化。线段可以理解为薄的局部对流扩散结构，其中扩散过程通过压缩应变增强。从DNS，它表明，边缘分布函数的长度$\ell$假设完全自相似时，重新缩放的平均长度$\ell_m$。由$Δϕ$和$\ell$的联合统计量可以定义局部梯度$g=Δϕ/\ell$，它在理解湍流混合和流动结构方面起着重要作用。$g$的大值出现在小但有限的长度尺度上。$g$的统计特征是罕见但强烈的偏差，超过标准偏差一个数量级以上。结果表明，这些事件打破了完整的自相似性的线段，这证实了标准的湍流范式，强烈的事件（这是被称为内部不连续性）是不自相似的。
A universal relation between intermittency and dissipation within and beyond homogeneous isotropic turbulence
Univ. Grenoble Alpes, CNRS, Grenoble INP（格勒诺布尔阿尔卑斯大学、法国国家科学研究中心、格勒诺布尔理工学院）；Institut für Physik und ForWind, Universität Oldenburg（奥尔登堡大学物理与风电研究所）；Univ. Lille, CNRS, ONERA, Arts et Métiers ParisTech, Centrale Lille（里尔大学、法国国家科学研究中心、法国航空国防技术局、巴黎国立高等工艺学院、中央理工学院）
Multiscale Turbulence Synthesis: Validation in 2D Hydrodynamics
Laboratoire de Physique de l’École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité（巴黎高等师范学院物理实验室，ENS，PSL大学，CNRS，索邦大学，巴黎西岱大学）；Observatoire de Paris, PSL University, Sorbonne Université, LERMA（巴黎天文台，PSL大学，索邦大学，LERMA）；Institut de recherche en astrophysique et planétologie UniversitT́oulouse III - Paul Sabatier, Observatoire Midi-Pyrénées, Centre National de la Recherche Scientifique, UMR5277（天体物理学与行星学研究所，图卢兹第三大学-保罗萨巴蒂尔，南比利牛斯天文台，法国国家科学研究中心，UMR5277）；Sorbonne Université, CNRS, UMR7095, Institut d’Astrophysique de Paris（索邦大学，CNRS，UMR7095，巴黎天体物理研究所）；DPHY, ONERA, Université Paris-Saclay（物理与应用数学系，ONERA，巴黎萨克雷大学）
