http://yetl.yabesh.ir/yetl1/handle/yetl/19004 2026-07-04T10:58:14Z 2026-07-04T10:58:14Z Yuqian Xi Wenqi Li Chendi Zhang Shikang Liu Chenyang Cao Pengcheng Li Yacun Yang Hao Zheng Weiwei Yao http://yetl.yabesh.ir/yetl1/handle/yetl/4309507 2026-02-16T21:38:25Z 2025-01-01T00:00:00Z

Flow Constrictions and Fish Behavior: Unraveling Undulatory Swimming Strategies in Accelerating Flow Yuqian Xi; Wenqi Li; Chendi Zhang; Shikang Liu; Chenyang Cao; Pengcheng Li; Yacun Yang; Hao Zheng; Weiwei Yao Section contractions in rivers often induce accelerated flows in nature, exerting substantial influence on the swimming behaviors of various fish species. This study focuses on the undulatory swimming strategies of fishes and the effects of hydrodynamics on the swimming behavior in a flume with constriction. By using a combination of computational fluid dynamics (CFD) modeling, convolutional neural network (CNN), and observation of fish behavior with kinematic and morpho-kinematic parameters, we investigate how fish select their swimming strategies when encountering complex flow conditions. The results reveal that fish exhibit distinct swimming behaviors in response to accelerating flows, including avoidance behavior, drifting with the flow, and escaping upstream. Fish demonstrate a preference for swimming on one side of the flume, with the side bank of the adaptation region being the most favored location due to the lower flow velocity and thigmotactic behavior. Additionally, we identify three swimming gaits employed by the fish to navigate complex river environments, adjusting their swimming behavior based on environmental cues. This study highlights the significance of both head and tail characteristics in governing fish swimming behavior, with head features crucial for perceiving the environment and tail movements directly influencing swimming speed and maneuverability.

2025-01-01T00:00:00Z Giulia Stradiotti Giuseppe Roberto Pisaturo Markus Noack Maurizio Righetti http://yetl.yabesh.ir/yetl1/handle/yetl/4309506 2026-02-16T21:38:23Z 2025-01-01T00:00:00Z

Velocity Profiles in Gravel Beds Based on Refractive Index Matching Experiments Giulia Stradiotti; Giuseppe Roberto Pisaturo; Markus Noack; Maurizio Righetti The space-and time-averaged velocity profiles in gravel beds show some features that differentiates them from that established in smooth beds, but the obstruction posed by the gravel hampers the experimental measurements below the sediments. To overcome such difficulties, we coupled particle image velocimetry (PIV) with refractive index matching (RIM) by means of substituting the gravel with hydrogel spheres. We applied a superposition of models on the experimental velocity profile: the Darcy, the mixing, the logarithmic, and the wake law models. The resulting analytical profile is adherent to the experimental data in all the regions of the flow, from the bottom to the free surface. After including a second data set from literature, we carried out the dimensional analyses on the parameters in the profile, defining them as functions of the general characteristics of the flow and of the bed. In particular, the position of the inflection point, and thus the relative contribution of the mixing and the logarithmic layers on the overall profile, were found to be related to the permeability Reynolds number.

2025-01-01T00:00:00Z Yaohui Chen Shangtuo Qian Yu Qian David Z. Zhu Jiangang Feng Hui Xu http://yetl.yabesh.ir/yetl1/handle/yetl/4309505 2026-02-16T21:38:21Z 2025-01-01T00:00:00Z

Prediction of Geyser Occurrences in Covered Manholes of Urban Stormwater Systems Yaohui Chen; Shangtuo Qian; Yu Qian; David Z. Zhu; Jiangang Feng; Hui Xu Storm geysers are air–water eruptions from stormwater manholes during intense rainfalls, which raise public safety concerns. They arise from entrapped air release in stormwater tunnels as flow transitions from open to pressurized. This paper experimentally investigated air–water flow characteristics during air pocket release in covered manholes. Four geyser regimes were identified: no geyser, single air-release geyser, single rapid-filling geyser, and multigeysers. The air-release geyser and rapid-filling geyser refer to ejections of water column and air–water mixture induced by distinct mechanisms. Impacts of manhole diameter, cover ventilation area, system pressure head, and initial air pocket volume on geyser regimes were analyzed. As manhole diameter increases or cover ventilation area decreases, maximum geyser heights decrease, subsequently decreasing the likelihood of geyser occurrence. Higher system pressure head and larger initial air pocket volume increase the maximum geyser heights. Equations were derived to predict the maximum geyser heights, and prediction accuracies exceeded 87%, providing safe predictions of geyser occurrences relative to the manhole height. The findings can help provide advance warning of geysers when combined with information of stormwater system structures and real-time monitoring of operating conditions.

2025-01-01T00:00:00Z Vitor G. Geller Yichen Tao Abdulmuttalib Lokhandwala Jose G. Vasconcelos Daniel B. Wright Ben R. Hodges http://yetl.yabesh.ir/yetl1/handle/yetl/4309504 2026-02-16T21:38:19Z 2025-01-01T00:00:00Z

Evaluating SWMM Modeling Performance for Rapid Flows on Tunnels with Geometric Discontinuities Vitor G. Geller; Yichen Tao; Abdulmuttalib Lokhandwala; Jose G. Vasconcelos; Daniel B. Wright; Ben R. Hodges The EPA’s Storm Water Management Model (SWMM) has been applied across the globe for citywide stormwater modeling due to its robustness and versatility. Recent research indicated that SWMM, with proper setup, can be applied in the description of more dynamic flow conditions, such as rapid inflow conditions. However, stormwater systems often have geometric discontinuities that can pose challenges to SWMM model accuracy, and this issue is poorly explored in the current literature. The present work evaluates the performance of SWMM 5 in the context of a real-world stormwater tunnel with a geometric discontinuity. Various combinations of spatiotemporal discretization are systematically evaluated along with four pressurization algorithms, and results are benchmarked with another hydraulic model using tunnel inflow simulations. Results indicated that the pressurization algorithm has an important effect on SWMM’s accuracy in conditions of sudden diameter changes. From the tested pressurization algorithms, the original Preissmann slot algorithm was the option that yielded more representative results for a wider range of spatiotemporal discretizations. Regarding spatiotemporal discretization options, intermediate discretization, and time steps that lead to Courant numbers equal to one performed best. Interestingly, the traditional SWMM’s link-node approach also presented numerical instabilities despite having low continuity errors. Results indicated that although SWMM can be effective in simulating rapid inflow conditions in tunnels, situations with drastic geometric changes need to be carefully evaluated so that modeling results are representative.

2025-01-01T00:00:00Z