Viscoelastic flows play an important role in numerous engineering fields,and the multiscale algorithms for simulating viscoelastic flows have received significant attention in order to deepen our understanding of the ...Viscoelastic flows play an important role in numerous engineering fields,and the multiscale algorithms for simulating viscoelastic flows have received significant attention in order to deepen our understanding of the nonlinear dynamic behaviors of viscoelastic fluids.However,traditional grid-based multiscale methods are confined to simple viscoelastic flows with short relaxation time,and there is a lack of uniform multiscale scheme available for coupling different solvers in the simulations of viscoelastic fluids.In this paper,a universal multiscale method coupling an improved smoothed particle hydrodynamics(SPH)and multiscale universal interface(MUI)library is presented for viscoelastic flows.The proposed multiscale method builds on an improved SPH method and leverages the MUI library to facilitate the exchange of information among different solvers in the overlapping domain.We test the capability and flexibility of the presented multiscale method to deal with complex viscoelastic flows by solving different multiscale problems of viscoelastic flows.In the first example,the simulation of a viscoelastic Poiseuille flow is carried out by two coupled improved SPH methods with different spatial resolutions.The effects of exchanging different physical quantities on the numerical results in both the upper and lower domains are also investigated as well as the absolute errors in the overlapping domain.In the second example,the complex Wannier flow with different Weissenberg numbers is further simulated by two improved SPH methods and coupling the improved SPH method and the dissipative particle dynamics(DPD)method.The numerical results show that the physical quantities for viscoelastic flows obtained by the presented multiscale method are in consistence with those obtained by a single solver in the overlapping domain.Moreover,transferring different physical quantities has an important effect on the numerical results.展开更多
A hierarchical model is developed to predict the streaming potential （SP） in the canaliculi of a loaded os teon. Canaliculi are assumed to run straight across the os teon annular cylinder wall, while disregarding th...A hierarchical model is developed to predict the streaming potential （SP） in the canaliculi of a loaded os teon. Canaliculi are assumed to run straight across the os teon annular cylinder wall, while disregarding the effect of lacuna. SP is generalized by the canalicular fluid flow. Ana lytical solutions are obtained for the canalicular fluid veloc ity, pressure, and SP. Results demonstrate that SP amplitude （SPA） is proportional to the pressure difference, strain am plitude, frequency, and strain rate amplitude. However, the key loading factor governing SP is the strain rate, which is a representative loading parameter under the specific phys iological state. Moreover, SPA is independent of canalicu lar length. This model links external loads to the canalicu lar fluid pressure, velocity, and SP, which can facilitate fur ther understanding of the mechanotransduction and electro mechanotransduction mechanisms of bones.展开更多
Oscillatory flow facilitates gas exchange in human respiration system. In the present study, both numerical calculation and PIV (Particle Image Velocimetry) measurement indicate that, under the application of HFOV (Hi...Oscillatory flow facilitates gas exchange in human respiration system. In the present study, both numerical calculation and PIV (Particle Image Velocimetry) measurement indicate that, under the application of HFOV (High Frequency Oscillatory Ventilation), apparent steady streaming is caused and augmented in distal airways by the continuous oscillation, i.e., the core air moves downwards and the peripheral air evacuates upwards within bronchioles. The net flow of steady streaming serves to overcome the lack of tidal volume in HFOV and delivers fresh air into deeper lung region. Also, numerical calculations reveal that the intensity of steady streaming is mainly influenced by the geometry of airways with provided oscillatory frequency and tidal volume, and it rises with Re and Wo up to a Re of about 124 and Wo of about 5. Steady streaming is considered as an important factor for the ventilation efficiency of HFOV.展开更多
The Chicago Area Waterway System(CAWS)is a 133.9 km branching network of navigable waterways controlled by hydraulic structures,in which the majority of the flow is treated wastewater effluent and there are periods of...The Chicago Area Waterway System(CAWS)is a 133.9 km branching network of navigable waterways controlled by hydraulic structures,in which the majority of the flow is treated wastewater effluent and there are periods of substantial combined sewer overflows.The CAWS comprises a network of effluent dominated streams.More stringent dissolved oxygen(DO)standards and a reduced flow augmentation allowance have been recently applied to the CAWS.Therefore,a carefully calibrated and verified one-dimensional flow and water quality model was applied to the CAWS to determine emission-based real-time control guidelines for the operation of flow augmentation and aeration stations.The goal of these guidelines was to attain DO standards at least 95%of the time.The“optimal”guidelines were tested for representative normal,dry,and wet years.The finally proposed guidelines were found in the simulations to attain the 95%target for nearly all locations in the CAWS for the three test years.The developed operational guidelines have been applied since 2018 and have shown improved attainment of the DO standards throughout the CAWS while at the same time achieving similar energy use at the aeration stations on the Calumet River system,greatly lowered energy use on the Chicago River system,and greatly lowered discretionary diversion from Lake Michigan,meeting the recently enacted lower amount of allowed annual discretionary diversion.This case study indicates that emission-based real-time control developed from a well calibrated model holds potential to help many receiving water bodies achieve high attainment of water quality standards.展开更多
The User Interface Transition Diagram (UITD) is a formal modeling notation that simplifies the specification and design of user-system interactions. It is a valuable communication tool for technical and non-technical ...The User Interface Transition Diagram (UITD) is a formal modeling notation that simplifies the specification and design of user-system interactions. It is a valuable communication tool for technical and non-technical stakeholders during the requirements elicitation phase, as it provides a simple yet technically complete notation that is easy to understand. In this paper, we investigated the efficiency of creating UITDs using draw.io, a widely used diagramming software, compared to a dedicated UITD editor. We conducted a study to compare the time required to use each tool to complete the task of creating a medium size UITD, as well as the subjective ease of use and satisfaction of participants with the dedicated Editor. Our results show that the UITD editor is more efficient and preferred by participants, highlighting the importance of using specialized tools for creating formal models such as UITDs. The findings of this study have implications for software developers, designers, and other stakeholders involved in the specification and design of user-system interactions.展开更多
基金Project supported by the National Natural Science Foundation of China(No.52109068)the Water Conservancy Technology Project of Jiangsu Province of China(No.2022060)。
文摘Viscoelastic flows play an important role in numerous engineering fields,and the multiscale algorithms for simulating viscoelastic flows have received significant attention in order to deepen our understanding of the nonlinear dynamic behaviors of viscoelastic fluids.However,traditional grid-based multiscale methods are confined to simple viscoelastic flows with short relaxation time,and there is a lack of uniform multiscale scheme available for coupling different solvers in the simulations of viscoelastic fluids.In this paper,a universal multiscale method coupling an improved smoothed particle hydrodynamics(SPH)and multiscale universal interface(MUI)library is presented for viscoelastic flows.The proposed multiscale method builds on an improved SPH method and leverages the MUI library to facilitate the exchange of information among different solvers in the overlapping domain.We test the capability and flexibility of the presented multiscale method to deal with complex viscoelastic flows by solving different multiscale problems of viscoelastic flows.In the first example,the simulation of a viscoelastic Poiseuille flow is carried out by two coupled improved SPH methods with different spatial resolutions.The effects of exchanging different physical quantities on the numerical results in both the upper and lower domains are also investigated as well as the absolute errors in the overlapping domain.In the second example,the complex Wannier flow with different Weissenberg numbers is further simulated by two improved SPH methods and coupling the improved SPH method and the dissipative particle dynamics(DPD)method.The numerical results show that the physical quantities for viscoelastic flows obtained by the presented multiscale method are in consistence with those obtained by a single solver in the overlapping domain.Moreover,transferring different physical quantities has an important effect on the numerical results.
基金supported by the OIT of Higher Learning Institutions of Shanxithe National Natural Science Foundation of China(11302143,11472185)Natural Science Fund of Shanxi(2014021013)
文摘A hierarchical model is developed to predict the streaming potential （SP） in the canaliculi of a loaded os teon. Canaliculi are assumed to run straight across the os teon annular cylinder wall, while disregarding the effect of lacuna. SP is generalized by the canalicular fluid flow. Ana lytical solutions are obtained for the canalicular fluid veloc ity, pressure, and SP. Results demonstrate that SP amplitude （SPA） is proportional to the pressure difference, strain am plitude, frequency, and strain rate amplitude. However, the key loading factor governing SP is the strain rate, which is a representative loading parameter under the specific phys iological state. Moreover, SPA is independent of canalicu lar length. This model links external loads to the canalicu lar fluid pressure, velocity, and SP, which can facilitate fur ther understanding of the mechanotransduction and electro mechanotransduction mechanisms of bones.
文摘Oscillatory flow facilitates gas exchange in human respiration system. In the present study, both numerical calculation and PIV (Particle Image Velocimetry) measurement indicate that, under the application of HFOV (High Frequency Oscillatory Ventilation), apparent steady streaming is caused and augmented in distal airways by the continuous oscillation, i.e., the core air moves downwards and the peripheral air evacuates upwards within bronchioles. The net flow of steady streaming serves to overcome the lack of tidal volume in HFOV and delivers fresh air into deeper lung region. Also, numerical calculations reveal that the intensity of steady streaming is mainly influenced by the geometry of airways with provided oscillatory frequency and tidal volume, and it rises with Re and Wo up to a Re of about 124 and Wo of about 5. Steady streaming is considered as an important factor for the ventilation efficiency of HFOV.
基金supported by the Metropolitan Water Reclamation District of Greater Chicago(Requisition No.1449764).
文摘The Chicago Area Waterway System(CAWS)is a 133.9 km branching network of navigable waterways controlled by hydraulic structures,in which the majority of the flow is treated wastewater effluent and there are periods of substantial combined sewer overflows.The CAWS comprises a network of effluent dominated streams.More stringent dissolved oxygen(DO)standards and a reduced flow augmentation allowance have been recently applied to the CAWS.Therefore,a carefully calibrated and verified one-dimensional flow and water quality model was applied to the CAWS to determine emission-based real-time control guidelines for the operation of flow augmentation and aeration stations.The goal of these guidelines was to attain DO standards at least 95%of the time.The“optimal”guidelines were tested for representative normal,dry,and wet years.The finally proposed guidelines were found in the simulations to attain the 95%target for nearly all locations in the CAWS for the three test years.The developed operational guidelines have been applied since 2018 and have shown improved attainment of the DO standards throughout the CAWS while at the same time achieving similar energy use at the aeration stations on the Calumet River system,greatly lowered energy use on the Chicago River system,and greatly lowered discretionary diversion from Lake Michigan,meeting the recently enacted lower amount of allowed annual discretionary diversion.This case study indicates that emission-based real-time control developed from a well calibrated model holds potential to help many receiving water bodies achieve high attainment of water quality standards.
文摘The User Interface Transition Diagram (UITD) is a formal modeling notation that simplifies the specification and design of user-system interactions. It is a valuable communication tool for technical and non-technical stakeholders during the requirements elicitation phase, as it provides a simple yet technically complete notation that is easy to understand. In this paper, we investigated the efficiency of creating UITDs using draw.io, a widely used diagramming software, compared to a dedicated UITD editor. We conducted a study to compare the time required to use each tool to complete the task of creating a medium size UITD, as well as the subjective ease of use and satisfaction of participants with the dedicated Editor. Our results show that the UITD editor is more efficient and preferred by participants, highlighting the importance of using specialized tools for creating formal models such as UITDs. The findings of this study have implications for software developers, designers, and other stakeholders involved in the specification and design of user-system interactions.
