Journal of Hydrodynamics最新文献

{"title":"Retrofitting low-performance units to abate sewer overflow pollution based on mathematical model and Sobol algorithm","authors":"Zhi-chao Zhao,&nbsp;Xiao-min Huang,&nbsp;Hai-long Yin,&nbsp;Jun-bo Wen,&nbsp;Xiao-wei Fu","doi":"10.1007/s42241-023-0048-5","DOIUrl":"10.1007/s42241-023-0048-5","url":null,"abstract":"<div><p>Optimal retrofit of low-performance units (LPUs) is promising to abate overflow pollutant mass loading of sewer systems during wet-weathers. This study presents a combination of mathematical model and Sobol algorithm to help identify LPUs of sewer systems and design retrofitting strategies. Therefore, the solution to minimize the overflow pollutant mass loading from sewers systems can be efficiently obtained. The developed method was demonstrated at a catchment served by one wastewater treatment plant in the Chaohu City, Anhui Province of China, with five pumping stations and a total sewer length of 58.3 km. Within the catchment, there are three rivers and a small lake to receive overflows from the sewer system. Among them, one river that was mostly polluted was selected as the object of overflow pollution abatement during wet weather period. After identifying the LPUs of the sewer system and developing retrofitting strategies using Sobol sequence, the mitigation of overflow pollution during wet weather period was analyzed. Results show that the mass loading of chemical oxygen demand (COD) discharged into the target river could be reduced by 40.6%, by implementing optimal retrofit strategy of LPUs, i.e., increasing the conveyance capacities of two pumping stations by 2.5–3.2 times and augmenting the diameters of 12 sewers by 1.25–1.29 times. To further coordinate the abatement of overflow pollution and retrofit investment, Sobol sensitivity analysis was conducted to screen the dominant LPUs to update the optimal retrofit strategy. By applying the updated strategy, the overflow COD mass loading per overflow event was close to that of non-updated strategy, while the retrofitting length of sewers was reduced by 40%. Therefore, on the basis of the presented method, decision-makers can flexibly develop retrofitting strategies of sewer system to abate overflow pollution during wet weathers in a cost-effective way.\u0000</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71909429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative study of reduced-order modeling method for the cavitating flow over a hydrofoil","authors":"Yan-zhao Wu,&nbsp;Ran Tao,&nbsp;Di Zhu,&nbsp;Ruo-fu Xiao","doi":"10.1007/s42241-023-0046-7","DOIUrl":"10.1007/s42241-023-0046-7","url":null,"abstract":"<div><p>As a high-dimensional complex nonlinear dynamic system, the analysis of the essence of flow has always been a difficult problem, especially in the flow including phase change. In recent years, it has become a feasible method to reduce the dimension of flow structure by reduced-order modeling (ROM) methods. In this paper, through the cavitation numerical simulation of NACA0015 hydrofoil, two ROM methods are used to reduce and restore three different cavitation respectively-proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD). The applicability of two methods in cavitation is discussed and reasons are analyzed. The results show that for stable cavitation, POD, DMD methods can accurately restore the flow field of a few modes with high energy. For unstable cavitation, only POD method can restore real flow field well. This situation is mainly due to the fact that POD, DMD method are applicable to different energy ratios, and different main mode selection criterion of DMD will lead to different main mode. ROM can greatly simplify the complexity of flow. Selecting a reasonable ROM can improve the accuracy of a small amount of database, and provide a basis for intelligent prediction of flow analysis.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71909427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Flow hydrodynamics drive effective fish attraction behaviour into slotted fishway entrances","authors":"Maryam Farzadkhoo,&nbsp;Richard T. Kingsford,&nbsp;Iain M. Suthers,&nbsp;Stefan Felder","doi":"10.1007/s42241-023-0047-6","DOIUrl":"10.1007/s42241-023-0047-6","url":null,"abstract":"<div><p>Effective fishways rely on attracting fish, utilising the natural rheotactic behaviour of fish to orient into an attraction flow near the entrance. Despite the critical importance of attraction, understanding of the hydrodynamics of vertical slot entrances in relation to fish behaviour remains poor. Herein, hydrodynamic measurements of flows at slotted fishway entrances were experimented with two different designs, two velocities, three water depths, and two fish species, silver perch (<i>Bidyanus bidyanus</i>) and Australian bass (<i>Percalates novemaculeata</i>). Fish behaviours were tracked in relation to hydrodynamic measures of three-dimensional velocity and turbulent kinetic energy (TKE). There were distinct differences in the attraction flow between entrance designs, irrespective of velocity and water depth. A plain slotted entrance produced a more symmetric flow in the centre of the flume, causing fish to approach the entrance by skirting the core of the attraction jet flow and areas of high turbulence. In contrast, streamlined slotted entrance design resulted in an asymmetric attraction flow which guided fish along the wingwall towards the slotted entrance, improving attraction for both species. There were clear patterns in swimming trajectories for silver perch, swimming along the sidewalls of the observation zone towards the entrance, but Australian bass were less predictable, using random routes on their way to the slotted entrance. Both species preferred areas of low turbulence (TKE &lt; 0.02 m² / s²). This work has important implications for design of vertical slotted entrance systems.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71909430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Double-plume Lagrangian particle tracking model and its application in deep water oil spill","authors":"Xin-wei Ye,&nbsp;Xiao-jing Niu,&nbsp;Jian Jiang","doi":"10.1007/s42241-023-0043-x","DOIUrl":"10.1007/s42241-023-0043-x","url":null,"abstract":"<div><p>Due to the density stratification of sea water, the dispersed oil droplets and gas bubbles with small diameters, as well as the dissolved components, may remain in some specific depths. The double-plume Lagrangian particle tracking model for bubbly plumes in vertical density stratified environments is improved and applied to predict the underwater pollutants in a blowout. This model considers the different properties and dissolution processes of components in crude oil and focuses on their behavior and stratification differences in the plume. The crude oil components are divided into several groups and the dissolution of oil and gas is also considered. The model is applied to simulate the “Deepwater Horizon” oil spill accident in the Gulf of Mexico in 2010. The results show several enrichment layers of oil and gas at different depth and the differences in concentration between components, which corresponds to the distribution of petroleum pollutants in the in-situ observation.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s42241-023-0043-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4595695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of IITM-RANS3D to free-fall water entry of prismatic and non-prismatic finite wedges","authors":"Shaswat Saincher,&nbsp;Kshitij Srivastava,&nbsp;R. Vijayakumar,&nbsp;V. Sriram","doi":"10.1007/s42241-023-0040-0","DOIUrl":"10.1007/s42241-023-0040-0","url":null,"abstract":"<div><p>High-speed watercraft and ships undergo coupled motions which make the front portion of the hull exit and violently re-enter water. This induces short-term slamming loads that may compromise the structural integrity of the hull. The slamming of the bow can be modeled as straight wedges of different deadrise angles (DRAs) falling into water from different heights. The advent of computational fluid dynamics has allowed the problem of wedge-slamming to be simulated using the full Navier-Stokes equations thus complementing the pioneering studies based on experiments. Recently, most researchers are opting to use commercial software to simulate the wedge-impact problem as it allows access to overset meshing algorithms which are robust in modeling the wedge as a moving body. Embedded boundary methods (EBMs) offer some advantages over overset meshing in that the mesh only needs to be generated once and Cartesian mesh-based solvers can be implemented. However, the application of EBMs to wedge-impact has been limited in the literature and merits further development. In this context, we investigate the applicability of the fast-fictitious-domain (FFD) based embedded boundary treatment to simulate the violent water-entry of wedges. We extend our in-house Navier-Stokes model IITM-RANS3D to handle floating bodies through integration of a rigid-body dynamics solver and an algorithm to embed three-dimensional stereolithography (STL) geometries as solids over a Cartesian mesh. The proposed algorithm is extensively benchmarked against variable DRA wedge-slamming experiments reported in the literature as well as constant DRA wedge-slamming experiments performed in-house. Very good agreement is reported in terms of the time-history of hydrodynamic impact pressures measured at various locations on the hull as well as the wedge motion responses thus demonstrating the suitability of FFD for simulating the coupled hydrodynamics of slamming for simplified hull geometries.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4599416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"LES investigation of the tip vortex cavitating flow with special emphasis on the interaction between cavitation and vorticity by a modified cavitation model","authors":"Xin-ran Liu,&nbsp;Tao Wang,&nbsp;Xiao-yang Zhao,&nbsp;Tai-ran Chen","doi":"10.1007/s42241-023-0045-8","DOIUrl":"10.1007/s42241-023-0045-8","url":null,"abstract":"<div><p>Cavitation within the tip vortex (TV) flow remains a challenging issue in the design of high-speed and low-noise hydraulic machinery. In this paper, the TV cavitating flow around an elliptical hydrofoil is calculated by using large eddy simulation (LES) combined with a modified Schnerr-Sauer (S-S) cavitation model. The original S-S cavitation model is modified by taking into account the typical effect of vortex flow. The partial pressure term which can describe the vortex quantitatively and qualitatively is confirmed as <i>ρ</i>_<i>m</i><i>ω</i><span>\u0000 ^<i>2</i>_<i>x</i>\u0000 \u0000 </span><i>r</i><span>\u0000 ^<i>2</i>_<i>c</i>\u0000 \u0000 </span>, and is considered into the R-P equation of the modified S-S cavitation model. Comparison between the numerical and experimental results shows good agreement in the form and evolution of cavities, including attached cavities (AC) and tip vortex cavities (TVC). The vorticity transport equation is utilized to investigate the dynamic mechanisms of the vortex development around the TVC. Further analyses indicate that cavitation in the TV flow influences the pressure in the core of the cavity and the local flow patterns. Typical vortex structures in the TV cavitating flow include TV, secondary vortex (SV) and wake vortex (WV). The direction and magnitude of the rotation effect can be described by axial vorticity which is drawn on the iso-surface of <i>Q</i> = 1 × 10⁵ s⁻². The development of the TV cavitating flow can be divided into two stages: Stage I, the development and fusion of TV, SV, stage II, the dissipation of SV. The stretching term dominates the evolution of TV, and the dilatation term is the main reason in the mergence process of SV.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4598385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The prediction of external flow field and hydrodynamic force with limited data using deep neural network","authors":"Tong-sheng Wang,&nbsp;Guang Xi,&nbsp;Zhong-guo Sun,&nbsp;Zhu Huang","doi":"10.1007/s42241-023-0042-y","DOIUrl":"10.1007/s42241-023-0042-y","url":null,"abstract":"<div><p>Predicting the external flow field with limited data or limited measurements has attracted long-time interests of researchers in many industrial applications. Physics informed neural network (PINN) provides a seamless framework for combining the measured data with the deep neural network, making the neural network capable of executing certain physical constraints. Unlike the data-driven model to learn the end-to-end mapping between the sensor data and high-dimensional flow field, PINN need no prior high-dimensional field as the training dataset and can construct the mapping from sensor data to high dimensional flow field directly. However, the extrapolation of the flow field in the temporal direction is limited due to the lack of training data. Therefore, we apply the long short-term memory (LSTM) network and physics-informed neural network (PINN) to predict the flow field and hydrodynamic force in the future temporal domain with limited data measured in the spatial domain. The physical constraints (conservation laws of fluid flow, e.g., Navier-Stokes equations) are embedded into the loss function to enforce the trained neural network to capture some latent physical relation between the output fluid parameters and input tempo-spatial parameters. The sparsely measured points in this work are obtained from computational fluid dynamics (CFD) solver based on the local radial basis function (RBF) method. Different numbers of spatial measured points (4–35) downstream the cylinder are trained with/without the prior knowledge of Reynolds number to validate the availability and accuracy of the proposed approach. More practical applications of flow field prediction can compute the drag and lift force along with the cylinder, while different geometry shapes are taken into account. By comparing the flow field reconstruction and force prediction with CFD results, the proposed approach produces a comparable level of accuracy while significantly fewer data in the spatial domain is needed. The numerical results demonstrate that the proposed approach with a specific deep neural network configuration is of great potential for emerging cases where the measured data are often limited.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4596713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical study on roll dynamics of damaged ship in beam waves and calm water","authors":"Zhi-yun Huang,&nbsp;Zhi-liang Gao,&nbsp;Sang-ming Xu","doi":"10.1007/s42241-023-0041-z","DOIUrl":"10.1007/s42241-023-0041-z","url":null,"abstract":"<div><p>Computational fluid dynamics is used to study the roll dynamics of a damaged ship in beam waves with various steepnesses and in calm water. The wave-making method, which combines the velocity-inlet boundary and momentum source with the fifth-order Stokes theory, is employed for wave generation. The SST <i>k</i>-<i>ω</i> turbulence model with a modification to the turbulent viscosity in Reynolds stress is adopted to prevent the over-production of turbulence in the numerical wave tank. The lateral drift restrained model with a combined dynamic mesh strategy is utilized to deal with the coupled heave-sway-roll motions of the ship. First, benchmarking tests are performed, including wave generation and roll response of the damaged ship in regular beam waves. Then, the effects of incident wave steepness on the roll response of the damaged ship are analyzed. For different wave steepnesses, the ship roll motion is dominated by the first-order harmonic component. The second-order component increases with the increase of wave steepness. Finally, the roll hydrodynamic coefficients for different parts of the damaged ship are investigated with different rolling parameters. The added moment of inertia for the whole damaged ship is mainly attributed to the external hull composition and changes slightly with the change of roll amplitude and frequency. The added moment of inertia for the compartments could be negative in particular cases. The damping coefficients of the whole damaged ship and external hull increase with the increase of roll amplitude and frequency, while that of the compartments appears complicated with the change of roll amplitude and frequency.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4601422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advances on numerical and experimental investigation of ship roll damping","authors":"Patrick Sumislawski,&nbsp;Moustafa Abdel-Maksoud","doi":"10.1007/s42241-023-0044-9","DOIUrl":"10.1007/s42241-023-0044-9","url":null,"abstract":"<div><p>This paper presents recent developments towards efficient and reliable methods for roll damping estimation based on numerical simulations as well as model tests using the harmonic excited roll motion (HERM) technique. A newly designed automatic roll damping estimation procedure shows the advantage of a just-in-time post processing of experimental measurement results. Real-time analysis of the measured roll damping values permits a considerable shortening of the test times. Thus, a large number of investigations can be carried out with relatively manageable effort in order to determine the roll damping behavior of different keel configurations or at operating conditions, e.g., different sized keels or Froude numbers. In addition, HERM measurement method is applied to investigate the memory effect. For this purpose, different excitation schemes are introduced and the results are analyzed. Moreover, a study of the scale effect on the roll damping properties is conducted, in which experimental and numerical investigations are performed for two scales of a ship model. Furthermore, a method is developed that significantly reduces the effort of Reynolds average Navier-Stokes (RANS)-based simulations of roll motion. The reduction of simulation time is achieved by introducing an artificial damping. The obtained results show that the developed method is very well applicable for numerical as well as in experimental investigations. During the model tests using HERM technique, the model is free and the rudder is used to keep the straight-ahead course. The analysis of the numerical and experimental results shows that the influence of the rudder induced force and moment during HERM tests is not negligible and the contribution of the rudder must be taken into account by estimating the roll damping. Finally, a new concept is developed to investigate the parametric roll behavior of ships, which allows neglecting the consideration of the complex modelling of free surface waves in the simulations. During the RANS computations, a potential-based method is applied to compute the variation of restoring terms due the roll motion.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4599422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of subgrid-scale models in wall-modeled large-eddy simulations of turbulent channel flows","authors":"Wei-wen Zhao,&nbsp;Fu-chang Zhou,&nbsp;Guo-qing Fan,&nbsp;De-cheng Wan","doi":"10.1007/s42241-023-0039-6","DOIUrl":"10.1007/s42241-023-0039-6","url":null,"abstract":"<div><p>Considering the demanding of grid requirements for high-Reynolds-number wall-bounded flow, the wall-modeled large-eddy simulation (WMLES) is an attractive method to deal with near wall turbulence. However, the effect of subgrid-scale (SGS) models for wall-bounded turbulent flow in combination with wall stress models is still unclear. In this paper, turbulent channel flow at <i>Re</i>_<i>τ</i> =1 000 are numerically simulated by WMLES in conjunction with four different SGS models, i.e., the wall-adapting local eddy-viscosity model, the dynamic Smagorinsky model, the dynamic SGS kinetic energy model and the dynamic Lagrangian model. The mean velocity profiles are compared with the law of the wall, and the velocity fluctuations are compared with direct numerical simulation data. The energy spectrum of velocity and wall pressure fluctuations are presented and the role of SGS models on predicting turbulent channel flow with WMLES is discussed.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5048230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}