Article
Engineering, Chemical
Sadaf Maramizonouz, Sadegh Nadimi
Summary: In this research, numerical simulations and twelve drag models were used to investigate the drag force acting on ellipsoidal particles. The results showed that most models compared well with the simulation results in terms of drag coefficient values and trends, although there was a significant range of maximum error.
Article
Biodiversity Conservation
Douglas Monteiro Cavalcante, Maria Tatiane Leonardo Chaves, Gabriella Moreira Campos, Jose Ramon Barros Cantalice, Genival Barros Junior
Summary: This study investigated the impact of flexible vegetation elements of Ipomoea pes-caprae species on water flow and sediment transport capacity. Results showed that aquatic vegetation directly influences river dynamics, with vegetation density having an impact on flow transport capacity. As the vegetation drag coefficient increases, it enhances the resistance to flow and reduces sediment transport capacity.
ECOLOGICAL INDICATORS
(2021)
Article
Ecology
Yu Bai, Weidong Xuan
Summary: This study investigates the influence of flexible vegetation roots on the hydraulic characteristics of an artificial floating bed (AFB) through experimental research. The formula for root resistance coefficient is obtained through a combination of theoretical analysis and machine learning. The results show that a higher density of fibrous roots leads to lower root resistance, and the drag force coefficient of flexible vegetation roots decreases with the increase of hydraulic parameter R-eh. The characteristic diameter d(50) is found to be the best parameter for describing root characteristics.
ECOLOGICAL ENGINEERING
(2022)
Article
Engineering, Civil
Parisa Setayesh, Hossein Afzalimehr
Summary: This study experimentally investigates the distributions of velocity in 3D in gravel bed channels with vegetation and examines six different methods for estimating bed shear stress. The distribution of shear stress is mainly controlled by the spatial distribution of vegetation and the biomechanical and architectural features of these plants, leading to a layered shape of shear stress near the bottom of the flume.
IRANIAN JOURNAL OF SCIENCE AND TECHNOLOGY-TRANSACTIONS OF CIVIL ENGINEERING
(2022)
Article
Environmental Sciences
Jennifer G. G. Duan, Khalid Al-Asadi
Summary: The study examined the impact of vegetation on bed form resistance and bed load transport in a mobile bed channel. It found that bed form resistance increases with vegetation concentration, while the bed load transport rate reduces with vegetation concentration.
Article
Environmental Sciences
Chenwei Zhao, Pablo Ouro, Thorsten Stoesser, Subhasish Dey, Hongwei Fang
Summary: Numerical simulations were conducted to explore the effects of natural bed roughness on bedload transport. The results show that as bed roughness increases, there is a shift in the velocity profiles, an increase in Reynolds stresses, and the fragmentation of coherent structures. The resting time of saltating particles increases while their saltation length, velocity, and angular velocity decrease.
WATER RESOURCES RESEARCH
(2022)
Article
Engineering, Civil
Walter Box, Juha Jarvela, Kaisa Vastila
Summary: This study investigates the flow resistance of flexible floodplain vegetation mixtures under a range of mean flow velocities and low relative submergences. The results show a significant decrease in flow resistance when the submergence increases, providing new evidence for extending LAI-based modeling to a wider range of vegetation densities. Adjustments to existing LAI-based approaches are needed for high water stages and the contribution of understory grasses to flow resistance should not be underestimated.
JOURNAL OF HYDROLOGY
(2021)
Article
Geosciences, Multidisciplinary
Zhilin Zhang, Bensheng Huang, Chao Tan, Xiangju Cheng
Summary: By investigating two damping factors and methods to calculate the drag coefficient through 99 experiments, this study found that the new method based on the relation between these two damping factors performed better than traditional methods in considering the emergent conditions of vegetation.
HYDROLOGY AND EARTH SYSTEM SCIENCES
(2021)
Article
Water Resources
R. Familkhalili, N. Tahvildari
Summary: A two-way fully coupled hydrodynamic-vegetation model was developed, successfully validated against laboratory experiments and further used to study the effects of vegetation on wave dynamics. The incorporation of a new mechanism for flexible vegetation in the wave model resulted in improved simulation results compared to rigid vegetation models.
ADVANCES IN WATER RESOURCES
(2022)
Article
Chemistry, Multidisciplinary
Antonino D'Ippolito, Francesco Calomino, Nadia Penna, Subhasish Dey, Roberto Gaudio
Summary: Even though fluid mechanics and numerical studies have made progress, experimental knowledge remains important for studying flow resistance in complex environments. This paper presents the results of experiments and simulations on the drag coefficients in open channels with emergent rigid vegetation. A regression equation was proposed to estimate the drag coefficients based on non-dimensional parameters, and it showed good results for different flow profiles.
APPLIED SCIENCES-BASEL
(2022)
Article
Engineering, Chemical
S. Neda Mehdizadeh, Amir Mehdi Pasdar, George G. Chase
Summary: This study focuses on the movement of liquid drops in fibrous media due to the drag force of the flowing gas phase. Through experiments and correlations, a model for the movement of drops in fiber media was established, providing a useful predictive tool for filter design.
SEPARATION AND PURIFICATION TECHNOLOGY
(2021)
Article
Environmental Sciences
Kourosh Nosrati, Hossein Afzalimehr, Jueyi Sui
Summary: Vegetation patches and strips play a crucial role in the protection of riverbanks and channel beds from erosion and sedimentation processes. This study investigated the drag coefficient of submerged flexible vegetation patches in gravel bed rivers. The results showed that the drag coefficient exhibited nonuniform variations with the increase in the Reynolds number, and two effects caused by flexible vegetation patches were observed.
Article
Materials Science, Multidisciplinary
Ryan Falkenstein-Smith, Kevin McGrattan
Summary: This study measured the wind resistance of different types of vegetation using a wind tunnel, finding significant variations among species. However, the differences observed may not have practical implications as they fall within the uncertainty bounds of the overall average drag coefficient.
FIRE AND MATERIALS
(2021)
Article
Engineering, Marine
Qiu-Pan Chen, Chun-Wei Bi, Zhi-Xing Zhang, Yun-Peng Zhao
Summary: Biofouling on netting is a significant problem that impacts hydrodynamics and water exchange. Physical model tests were conducted to investigate the drag effect of netting panels with artificial hard and flexible fouling. The results indicated that fouling can rapidly increase netting drag, with severe hard fouling causing a drag amplification factor up to 30 times higher than clean netting. The drag coefficients for artificial hard fouling were found to be up to 54% higher than those for flexible fouling. The proposed formulas for predicting drag coefficients can be used to evaluate cage safety in netting cage design.
Article
Engineering, Mechanical
Zi-Chao Zhang, Yan-Pin Li, Lan-Jin Zhang, De-Xin Chen
Summary: In this study, the calculation accuracy of the Wen-Yu drag force model is improved by introducing particle inertia and turbulence intensity factors, leading to the proposed modified turbulence effect (MTE)-Wen-Yu drag force modification model. The calculations show that the MTE-Wen-Yu model has higher accuracy compared to the original Wen-Yu model, especially for suspended-load sediment solid-liquid two-phase flow with small particle diameters.
JOURNAL OF FLUIDS AND STRUCTURES
(2023)
