Ross Henteleff, Jacob Stolle, Acacia Markov, Ion Nistor, V. Sriram
This paper evaluates the performance of a new flexible fluid-structure interaction (FSI) module in an open-source computational fluid dynamics (CFD) software - REEF3D - for use in modelling saltmarsh vegetation. Unlike previous studies, which focussed on hydrodynamic response to plants (for example, wave attenuation) to check the accuracy of their numerical modelling efforts, this work attempts to replicate the plants’ drag force and motion behavior, based on results from several physical modelling studies. The flexible FSI module was found to consistently overestimate both the drag and motion of the numerical plants when compared to their physical counterparts. It is hypothesized that this is due to the module’s use of linearly elastic material theory for the flexible structures. This is arguably inadequate for the relatively flexible materials of saltmarsh vegetation.
{"title":"The Performance of Flexible Fluid-Structure Interaction Module for Saltmarsh Vegetation Under Flow and Wave Action","authors":"Ross Henteleff, Jacob Stolle, Acacia Markov, Ion Nistor, V. Sriram","doi":"10.1139/cjce-2023-0193","DOIUrl":"https://doi.org/10.1139/cjce-2023-0193","url":null,"abstract":"This paper evaluates the performance of a new flexible fluid-structure interaction (FSI) module in an open-source computational fluid dynamics (CFD) software - REEF3D - for use in modelling saltmarsh vegetation. Unlike previous studies, which focussed on hydrodynamic response to plants (for example, wave attenuation) to check the accuracy of their numerical modelling efforts, this work attempts to replicate the plants’ drag force and motion behavior, based on results from several physical modelling studies. The flexible FSI module was found to consistently overestimate both the drag and motion of the numerical plants when compared to their physical counterparts. It is hypothesized that this is due to the module’s use of linearly elastic material theory for the flexible structures. This is arguably inadequate for the relatively flexible materials of saltmarsh vegetation.","PeriodicalId":9414,"journal":{"name":"Canadian Journal of Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139809485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, a finite element model was established to compute the responses of asphalt pavement with various bonding conditions between the asphalt concrete layers (AC-AC interface) and between the asphalt concrete layer and base (AC-Base interface). The influence of bonding conditions of different interfaces on failure mode of asphalt pavement was discussed. The results indicated that poor bonding condition would increase longitudinal tensile strain at the bottom of the AC layers and vertical compressive strain at the top of subgrade, and the negative effects of two interfaces on pavement would enhance each other. It was observed that insufficient bonding strength would reduce the predicted life of pavement and, more importantly, debonding of AC-AC interface or two interfaces simultaneously would change pavement failure mode. Additionally, it should be noted that the fully-unbonded condition of AC-AC interface would affect the critical location for crack initiation in AC layers.
本研究建立了一个有限元模型，以计算沥青混凝土层之间（AC-AC 接口）和沥青混凝土层与基层之间（AC-基层接口）具有不同粘结条件的沥青路面的响应。讨论了不同界面粘结条件对沥青路面破坏模式的影响。结果表明，粘结不良会增加沥青混凝土层底部的纵向拉应变和基层顶部的纵向压应变，两种界面对路面的负面影响会相互增强。据观察，粘结强度不足会降低路面的预测寿命，更重要的是，AC-AC 接口或两个接口同时脱粘将改变路面的破坏模式。此外，应该注意的是，AC-AC 接口的完全未粘结状态会影响 AC 层裂缝萌发的临界位置。
{"title":"Influence of bonding condition of different interfaces on the mechanical responses and failure mode of asphalt pavement","authors":"Kang Yao, Q. Dong, Xueqin Chen, Xiang Wang, Sheng-hua Xie, Zhiqiang Cheng","doi":"10.1139/cjce-2023-0249","DOIUrl":"https://doi.org/10.1139/cjce-2023-0249","url":null,"abstract":"In this study, a finite element model was established to compute the responses of asphalt pavement with various bonding conditions between the asphalt concrete layers (AC-AC interface) and between the asphalt concrete layer and base (AC-Base interface). The influence of bonding conditions of different interfaces on failure mode of asphalt pavement was discussed. The results indicated that poor bonding condition would increase longitudinal tensile strain at the bottom of the AC layers and vertical compressive strain at the top of subgrade, and the negative effects of two interfaces on pavement would enhance each other. It was observed that insufficient bonding strength would reduce the predicted life of pavement and, more importantly, debonding of AC-AC interface or two interfaces simultaneously would change pavement failure mode. Additionally, it should be noted that the fully-unbonded condition of AC-AC interface would affect the critical location for crack initiation in AC layers.","PeriodicalId":9414,"journal":{"name":"Canadian Journal of Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140476824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents results of a research project completed to compare the ice melting capabilities of environmentally friendly alternative deicers with average road salt. Tests were conducted in an environmental chamber where temperatures could be controlled to a certain degree to ensure that the test specimens were in the ideal condition for the most accurate results. There were 168 samples tested and their results were recorded and interpreted throughout this paper. The outcome of this research is based off the amount of brine solution produced during the melting tests, and the depth of ice penetrated for the penetration test. The data showed that all alternative deicers competed evenly or in some cases slightly outperformed rock salt. The results show that there is no clear preference that can be given to the materials, the preference could only be given based off factors not related to the ice melting and penetration.
{"title":"An Investigation on the Deicing Potential of Road Salt and Alternative Deicers","authors":"Mitchell Lawlor, Kamal Hossain","doi":"10.1139/cjce-2023-0404","DOIUrl":"https://doi.org/10.1139/cjce-2023-0404","url":null,"abstract":"This paper presents results of a research project completed to compare the ice melting capabilities of environmentally friendly alternative deicers with average road salt. Tests were conducted in an environmental chamber where temperatures could be controlled to a certain degree to ensure that the test specimens were in the ideal condition for the most accurate results. There were 168 samples tested and their results were recorded and interpreted throughout this paper. The outcome of this research is based off the amount of brine solution produced during the melting tests, and the depth of ice penetrated for the penetration test. The data showed that all alternative deicers competed evenly or in some cases slightly outperformed rock salt. The results show that there is no clear preference that can be given to the materials, the preference could only be given based off factors not related to the ice melting and penetration.","PeriodicalId":9414,"journal":{"name":"Canadian Journal of Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139597614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The drag force exerted on a bridge abutment, representative of wall-attached structures, is studied with different geometries in various flow conditions. The drag force was quantified by two methods here: 1) direct method by using strain gauges and 2) employing the conservation of momentum equation which takes advantage of the flow characteristics. . The momentum equation results differed considerably from the direct method, mainly related to even the smallest inaccuracy in depth measurements. We suggest a modified momentum equation to enhance accuracy because of its independence on downstream flow depth measurement. The experimental results also revealed that the constriction ratio at the bridge abutment section and the abutments geometric shape are the most influential parameters on the drag coefficient. On the other hand, the effect of flow characteristics is negligible. Finally, we proposed an empirical relationship to estimate the drag coefficient.
{"title":"Experimental Study on the Drag force on Bridge Abutments","authors":"Hamid Reza Azarmidokht, A. Zarrati","doi":"10.1139/cjce-2023-0248","DOIUrl":"https://doi.org/10.1139/cjce-2023-0248","url":null,"abstract":"The drag force exerted on a bridge abutment, representative of wall-attached structures, is studied with different geometries in various flow conditions. The drag force was quantified by two methods here: 1) direct method by using strain gauges and 2) employing the conservation of momentum equation which takes advantage of the flow characteristics. . The momentum equation results differed considerably from the direct method, mainly related to even the smallest inaccuracy in depth measurements. We suggest a modified momentum equation to enhance accuracy because of its independence on downstream flow depth measurement. The experimental results also revealed that the constriction ratio at the bridge abutment section and the abutments geometric shape are the most influential parameters on the drag coefficient. On the other hand, the effect of flow characteristics is negligible. Finally, we proposed an empirical relationship to estimate the drag coefficient.","PeriodicalId":9414,"journal":{"name":"Canadian Journal of Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139604746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The seismic demands of the Reinforced Concrete Shear Walls (RCSWs) system are determined based on Canada's National Building Code (NBC). NBC 2020 features the revised Canadian Seismic Hazard Model (CSHM) and presents the possibility of enhancing demand's accuracy by determining design spectra based on the specific average shear wave velocity, instead of specified site classes. This paper investigates the changes in design demands for RCSWs compared to the previous edition. To do so, fifty-five RCSW prototypes were modelled using distributed mass and stiffness procedure, and their dynamic response was assessed through Modal Response Spectrum Analysis (MRSA) at five locations across Canada. The results highlight significant changes in deformation and force demands, where the majority of cases experienced an increase in 2020 compared to 2015 when demands were determined based on specified site classes. This study also evaluates the log-log interpolation method recommended by NBC 2020 for the design spectral acceleration.
{"title":"Implications of the 2020 National Building Code of Canada Updates on the Design Demands for Reinforced Concrete Shear Wall Buildings","authors":"Saeed Dehghani, L. Tobber","doi":"10.1139/cjce-2023-0111","DOIUrl":"https://doi.org/10.1139/cjce-2023-0111","url":null,"abstract":"The seismic demands of the Reinforced Concrete Shear Walls (RCSWs) system are determined based on Canada's National Building Code (NBC). NBC 2020 features the revised Canadian Seismic Hazard Model (CSHM) and presents the possibility of enhancing demand's accuracy by determining design spectra based on the specific average shear wave velocity, instead of specified site classes. This paper investigates the changes in design demands for RCSWs compared to the previous edition. To do so, fifty-five RCSW prototypes were modelled using distributed mass and stiffness procedure, and their dynamic response was assessed through Modal Response Spectrum Analysis (MRSA) at five locations across Canada. The results highlight significant changes in deformation and force demands, where the majority of cases experienced an increase in 2020 compared to 2015 when demands were determined based on specified site classes. This study also evaluates the log-log interpolation method recommended by NBC 2020 for the design spectral acceleration.","PeriodicalId":9414,"journal":{"name":"Canadian Journal of Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139609265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Short duration loads, such as impact loading, have the potential to generate catastrophic effects on infrastructure and loss of life. Although design provisions for engineered wood products are included in Canada’s blast design standard, CSA S850, how these structural materials respond to blast and impact loads across a wide range of high strain rates has not been well documented. An experimental program was carried out using a newly established Drop Weight Impact Testing Facility to investigate the flexural behaviour of glued-laminated timber beams subjected to impact loading. High-strain rates were generated, whereby the dynamic specimens were found to differ quantitatively and qualitatively from their quasi-static counterparts. Dynamic increase factors of 1.13 and 1.20 were observed on the peak resistance and initial stiffness, respectively. A single-degree-of-freedom model was developed and validated against the experimental test results, where it was found to accurately predict the displacement-time histories of the specimens until failure.
{"title":"Behaviour of glued-laminated timber beams under impact loading","authors":"Nicole Wight, C. Viau, Patrick P.J. Heffernan","doi":"10.1139/cjce-2023-0298","DOIUrl":"https://doi.org/10.1139/cjce-2023-0298","url":null,"abstract":"Short duration loads, such as impact loading, have the potential to generate catastrophic effects on infrastructure and loss of life. Although design provisions for engineered wood products are included in Canada’s blast design standard, CSA S850, how these structural materials respond to blast and impact loads across a wide range of high strain rates has not been well documented. An experimental program was carried out using a newly established Drop Weight Impact Testing Facility to investigate the flexural behaviour of glued-laminated timber beams subjected to impact loading. High-strain rates were generated, whereby the dynamic specimens were found to differ quantitatively and qualitatively from their quasi-static counterparts. Dynamic increase factors of 1.13 and 1.20 were observed on the peak resistance and initial stiffness, respectively. A single-degree-of-freedom model was developed and validated against the experimental test results, where it was found to accurately predict the displacement-time histories of the specimens until failure.","PeriodicalId":9414,"journal":{"name":"Canadian Journal of Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139612459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Structure, during its design period, may face unpredictable dynamic loading: wind, earthquake, and blast. Unavoidably, loading rates impact the dynamic behaviours of structures. Besides, the infrastructure system is more susceptible to dynamic loading. Therefore, a study on the dynamic behaviour of concrete under Quasi-Static cyclic load is inevitable. Fortunately, the researchers explored that innovative materials could respond better to extreme dynamic loading. One of the serious issues is the demolition of rubber tyres, which may be solved by converting the same into crumb form as an innovative construction material. In the present study, experimental and Finite Element Method based numerical analysis shows a substantial improvement in fatigue, flexural, ductility, inelastic performance and energy dissipation capacity of the Alcofine-based crumb rubber concrete beam. These performances are observed experimentally under monotonic and Quasi-Static cyclic loads. The load-carrying capacity has also been predicted analytically; the results agree with the experimental and numerical ones.
{"title":"Experimental and Numerical Performance analysis of Alccofine-based crumb rubber concrete under Quasi-Static cyclic Load","authors":"P. Haldar, Somnath Karmakar","doi":"10.1139/cjce-2023-0122","DOIUrl":"https://doi.org/10.1139/cjce-2023-0122","url":null,"abstract":"Structure, during its design period, may face unpredictable dynamic loading: wind, earthquake, and blast. Unavoidably, loading rates impact the dynamic behaviours of structures. Besides, the infrastructure system is more susceptible to dynamic loading. Therefore, a study on the dynamic behaviour of concrete under Quasi-Static cyclic load is inevitable. Fortunately, the researchers explored that innovative materials could respond better to extreme dynamic loading. One of the serious issues is the demolition of rubber tyres, which may be solved by converting the same into crumb form as an innovative construction material. In the present study, experimental and Finite Element Method based numerical analysis shows a substantial improvement in fatigue, flexural, ductility, inelastic performance and energy dissipation capacity of the Alcofine-based crumb rubber concrete beam. These performances are observed experimentally under monotonic and Quasi-Static cyclic loads. The load-carrying capacity has also been predicted analytically; the results agree with the experimental and numerical ones.","PeriodicalId":9414,"journal":{"name":"Canadian Journal of Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139616905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rahul Saini, Vahid Sadeghian, Jeffrey Erochko, David Lau
Construction of modular hospitals has gained significant attention since the global pandemic. One important design requirement for hospitals that is critical for their safe operation is to control floor vibration. Floors in modular buildings are often more prone to vibration because they are lightweight and less restrained. This study first presents a standardized design layout for modular hospitals developed based on Canadian code requirements. Then, the human-induced vibration of various floor systems designed for this sample modular hospital is investigated using different analysis methods including a new method developed by the authors. It is found that conventional floor designs may not be suitable for modular hospitals considering the strict vibration limits for hospitals and the need for lightweight construction. Using detailed FE analysis, it is shown that the proposed method can accurately predict the vibration response of various floors including those that have frequencies well beyond the application range of existing design methods.
自全球大流行病发生以来，模块化医院的建设受到了极大关注。医院安全运行的一个重要设计要求是控制地面振动。模块化建筑的地板通常更容易产生振动，因为它们重量轻、约束少。本研究首先介绍了根据加拿大规范要求开发的模块化医院标准化设计布局。然后，使用不同的分析方法，包括作者开发的一种新方法，对为该样本模块化医院设计的各种地板系统的人体诱发振动进行了研究。研究发现，考虑到医院严格的振动限制和轻质结构的需要，传统的地板设计可能并不适合模块化医院。详细的 FE 分析表明，所提出的方法可以准确预测各种地板的振动响应，包括那些频率远远超出现有设计方法应用范围的地板。
{"title":"Evaluation of Human-Induced Vibration in Floors of Modular Hospitals","authors":"Rahul Saini, Vahid Sadeghian, Jeffrey Erochko, David Lau","doi":"10.1139/cjce-2023-0091","DOIUrl":"https://doi.org/10.1139/cjce-2023-0091","url":null,"abstract":"Construction of modular hospitals has gained significant attention since the global pandemic. One important design requirement for hospitals that is critical for their safe operation is to control floor vibration. Floors in modular buildings are often more prone to vibration because they are lightweight and less restrained. This study first presents a standardized design layout for modular hospitals developed based on Canadian code requirements. Then, the human-induced vibration of various floor systems designed for this sample modular hospital is investigated using different analysis methods including a new method developed by the authors. It is found that conventional floor designs may not be suitable for modular hospitals considering the strict vibration limits for hospitals and the need for lightweight construction. Using detailed FE analysis, it is shown that the proposed method can accurately predict the vibration response of various floors including those that have frequencies well beyond the application range of existing design methods.","PeriodicalId":9414,"journal":{"name":"Canadian Journal of Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139617926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Effective winter road maintenance relies on precise road friction estimation. Machine learning (ML) models have shown significant promise in this; however, their inherent complexity makes understanding their inner workings challenging. This paper addresses this issue by conducting a comparative analysis of road friction estimation models using four ML methods, including regression tree, random forest, eXtreme Gradient Boosting (XGBoost), and support vector regression (SVR). We then employ the SHapley Additive exPlanations (SHAP) explainable artificial intelligence (AI) to enhance model interpretability. Our analysis on an Alberta dataset reveals that the XGBoost model performs best with an accuracy of 91.39%. The SHAP analysis illustrates the logical relationships between predictor features and friction within all three tree-based models, but it also uncovers inconsistencies within the SVR model, potentially attributed to insufficient feature interactions. Thus, this paper not only showcase the role of explainable AI in improving the ML interpretability of models for road friction estimation, but also provides practical insights that could improve winter road maintenance decisions.
有效的冬季道路养护有赖于精确的道路摩擦力估算。机器学习（ML）模型在这方面显示出了巨大的前景；然而，由于其固有的复杂性，了解其内部工作原理具有挑战性。本文针对这一问题，使用四种 ML 方法（包括回归树、随机森林、极梯度提升 (XGBoost) 和支持向量回归 (SVR)）对道路摩擦力估算模型进行了比较分析。然后，我们采用 SHapley Additive exPlanations (SHAP) 可解释人工智能 (AI) 来增强模型的可解释性。我们对阿尔伯塔省数据集的分析表明，XGBoost 模型的准确率为 91.39%，表现最佳。SHAP 分析表明了所有三种基于树的模型中预测特征与摩擦之间的逻辑关系，但也发现了 SVR 模型中的不一致之处，这可能是由于特征交互不足造成的。因此，本文不仅展示了可解释人工智能在改善道路摩擦力估算模型的 ML 可解释性方面的作用，还提供了可改善冬季道路维护决策的实用见解。
{"title":"Enhancing winter road maintenance with explainable AI: SHAP analysis for interpreting machine learning models in road friction estimation","authors":"Xueru Ding, Tae J. Kwon","doi":"10.1139/cjce-2023-0410","DOIUrl":"https://doi.org/10.1139/cjce-2023-0410","url":null,"abstract":"Effective winter road maintenance relies on precise road friction estimation. Machine learning (ML) models have shown significant promise in this; however, their inherent complexity makes understanding their inner workings challenging. This paper addresses this issue by conducting a comparative analysis of road friction estimation models using four ML methods, including regression tree, random forest, eXtreme Gradient Boosting (XGBoost), and support vector regression (SVR). We then employ the SHapley Additive exPlanations (SHAP) explainable artificial intelligence (AI) to enhance model interpretability. Our analysis on an Alberta dataset reveals that the XGBoost model performs best with an accuracy of 91.39%. The SHAP analysis illustrates the logical relationships between predictor features and friction within all three tree-based models, but it also uncovers inconsistencies within the SVR model, potentially attributed to insufficient feature interactions. Thus, this paper not only showcase the role of explainable AI in improving the ML interpretability of models for road friction estimation, but also provides practical insights that could improve winter road maintenance decisions.","PeriodicalId":9414,"journal":{"name":"Canadian Journal of Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139438257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The double-averaged (DA) turbulence characteristics over rough bed comprising of hemispherical elements with different spacing (p/r = 2, 4, 6, and 8; p = pitch distance; r = height of hemisphere) is quantified for three flow-submergences [h/r = 7.14, 5.35, 3.57; mean flow-depth (h)= 20 cm, 15 cm, and 10 cm]. The production and dissipation rates of turbulent kinetic energy are maximum at and below the crest level. Within interfacial sublayer, the degree of anisotropy is observed to be maximum for p/r = 4 and the tendency for the return to isotropy is strongest for p/r = 8 in the outer layer. The turbulence generated in the bottom region is still present in the outer region for low flow-submergences. The turbulence strength is maintained in the roughness order (descending) as p/r = 4 >2> 6 > 8 > plane bed; wherein the change in flow-submergence does not change this order.
{"title":"Effect of hemispherical roughness spacing on Double-averaged turbulence characteristics for different flow submergence","authors":"Jayanta Shounda, K. Barman, K. Debnath","doi":"10.1139/cjce-2023-0360","DOIUrl":"https://doi.org/10.1139/cjce-2023-0360","url":null,"abstract":"The double-averaged (DA) turbulence characteristics over rough bed comprising of hemispherical elements with different spacing (p/r = 2, 4, 6, and 8; p = pitch distance; r = height of hemisphere) is quantified for three flow-submergences [h/r = 7.14, 5.35, 3.57; mean flow-depth (h)= 20 cm, 15 cm, and 10 cm]. The production and dissipation rates of turbulent kinetic energy are maximum at and below the crest level. Within interfacial sublayer, the degree of anisotropy is observed to be maximum for p/r = 4 and the tendency for the return to isotropy is strongest for p/r = 8 in the outer layer. The turbulence generated in the bottom region is still present in the outer region for low flow-submergences. The turbulence strength is maintained in the roughness order (descending) as p/r = 4 >2> 6 > 8 > plane bed; wherein the change in flow-submergence does not change this order.","PeriodicalId":9414,"journal":{"name":"Canadian Journal of Civil Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139445135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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