Pub Date : 2022-02-07DOI: 10.1080/10618562.2021.2019227
Kaito Wada, T. Kurahashi
In this study, we present an investigation of shape optimisation analysis for a heat convection problem taking into account perimeter constraint condition. The incompressible Navier–Stokes equation using the Boussinesq approximation, the equation of continuity and the energy equation are employed for the governing equations in the heat convection field. The mixed interpolation method is applied to solve the flow field, and the quadratic and linear triangular elements are, respectively, employed for the velocity and the pressure. The quadratic triangular element is applied to interpolate the temperature. The purpose of this study is to find the optimal shape of a heat source so as to maximise the quantity of radiation on the outer boundary. The adjoint variable method is applied to obtain the optimal shape, and the perimeter constraint condition for the heat source is considered in this optimisation problem. The perimeter constraint condition is adapted in the traction method.
{"title":"Shape Optimisation of a Heat Source in a Thermal Convection Field Considering Perimeter Constraint Condition","authors":"Kaito Wada, T. Kurahashi","doi":"10.1080/10618562.2021.2019227","DOIUrl":"https://doi.org/10.1080/10618562.2021.2019227","url":null,"abstract":"In this study, we present an investigation of shape optimisation analysis for a heat convection problem taking into account perimeter constraint condition. The incompressible Navier–Stokes equation using the Boussinesq approximation, the equation of continuity and the energy equation are employed for the governing equations in the heat convection field. The mixed interpolation method is applied to solve the flow field, and the quadratic and linear triangular elements are, respectively, employed for the velocity and the pressure. The quadratic triangular element is applied to interpolate the temperature. The purpose of this study is to find the optimal shape of a heat source so as to maximise the quantity of radiation on the outer boundary. The adjoint variable method is applied to obtain the optimal shape, and the perimeter constraint condition for the heat source is considered in this optimisation problem. The perimeter constraint condition is adapted in the traction method.","PeriodicalId":56288,"journal":{"name":"International Journal of Computational Fluid Dynamics","volume":"57 1","pages":"92 - 102"},"PeriodicalIF":1.3,"publicationDate":"2022-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86575753","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}
Pub Date : 2022-02-07DOI: 10.1080/10618562.2022.2027391
T. Kurahashi, Kohei Ikarashi, Toshiaki Kenchi, Toshihiko Eto
In this paper, we present a data assimilation analysis in a shallow water flow field considering shoreline movement, based on the extended Kalman filter finite element method (extended Kalman filter FEM). It is known that if the combined method of the Kalman filter and the finite element method(FEM) is employed, a solution can be obtained that is closer to the practical observed value than that based on normal FEM. A dam-break problem is targeted in numerical experiments. In this study, the observed values used in the extended Kalman filter FEM are obtained by image analysis, and we investigate the estimation accuracy by changing the governing equation for shallow water flow.
{"title":"Data Assimilation of Water Elevation in Shallow Water Flow Based on the Extended Kalman Filter FEM Using Measurement Data from Image Analysis","authors":"T. Kurahashi, Kohei Ikarashi, Toshiaki Kenchi, Toshihiko Eto","doi":"10.1080/10618562.2022.2027391","DOIUrl":"https://doi.org/10.1080/10618562.2022.2027391","url":null,"abstract":"In this paper, we present a data assimilation analysis in a shallow water flow field considering shoreline movement, based on the extended Kalman filter finite element method (extended Kalman filter FEM). It is known that if the combined method of the Kalman filter and the finite element method(FEM) is employed, a solution can be obtained that is closer to the practical observed value than that based on normal FEM. A dam-break problem is targeted in numerical experiments. In this study, the observed values used in the extended Kalman filter FEM are obtained by image analysis, and we investigate the estimation accuracy by changing the governing equation for shallow water flow.","PeriodicalId":56288,"journal":{"name":"International Journal of Computational Fluid Dynamics","volume":"135 1","pages":"103 - 111"},"PeriodicalIF":1.3,"publicationDate":"2022-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86293003","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}
Recently, the unified gas-kinetic wave-particle (UGKWP) method was proposed to describe rarefied flows efficiently in all Knudsen numbers. However, the initial UGKWP method with the Bhatnagar–Gross–Krook (BGK) model has its own limitations due to the unit Prandtl number. To further improve its performance in non-equilibrium flows, the UGKWP method is extended for the ellipsoidal statistical model (ESBGK) and Shakhov model (SBGK) in this paper. The numerical results of shock structures of the above BGK-type models show that the SBGK model fits the reference data best except the asymmetry parameter, and the ESBGK model comes the second. Meanwhile, in order to overcome the deficiency of negative probability density function (PDF) in SBGK, the UGKWP method with positive-preserving Shakhov PDF is also constructed. It weakens the early rising of temperature phenomenon that existed in the SBGK model, and improves the performance in predicting the stress and heat flux evidently at high Mach numbers.
{"title":"Study of Shock Structures Using the Unified Gas-Kinetic Wave-Particle Method with Various BGK Models","authors":"Guo Fan, Wenwen Zhao, Zhongzheng Jiang, Weifang Chen","doi":"10.1080/10618562.2022.2082418","DOIUrl":"https://doi.org/10.1080/10618562.2022.2082418","url":null,"abstract":"Recently, the unified gas-kinetic wave-particle (UGKWP) method was proposed to describe rarefied flows efficiently in all Knudsen numbers. However, the initial UGKWP method with the Bhatnagar–Gross–Krook (BGK) model has its own limitations due to the unit Prandtl number. To further improve its performance in non-equilibrium flows, the UGKWP method is extended for the ellipsoidal statistical model (ESBGK) and Shakhov model (SBGK) in this paper. The numerical results of shock structures of the above BGK-type models show that the SBGK model fits the reference data best except the asymmetry parameter, and the ESBGK model comes the second. Meanwhile, in order to overcome the deficiency of negative probability density function (PDF) in SBGK, the UGKWP method with positive-preserving Shakhov PDF is also constructed. It weakens the early rising of temperature phenomenon that existed in the SBGK model, and improves the performance in predicting the stress and heat flux evidently at high Mach numbers.","PeriodicalId":56288,"journal":{"name":"International Journal of Computational Fluid Dynamics","volume":"37 1","pages":"44 - 62"},"PeriodicalIF":1.3,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88815263","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}
Pub Date : 2022-01-02DOI: 10.1080/10618562.2022.2070614
Naina Pisharoti, J. Webster, S. Brizzolara
Implementation of the SSG/LRR-ω-γ model is carried out in the current study to predict transition to turbulence. The framework uses a Reynolds stress transport model, SSG/LRR-ω, as the base turbulence formulation and is coupled with Menter's γ transition model. To extend its applicability to different transition mechanisms, the production terms in the Reynolds stress and specific dissipation rate transport equations are modified. SSG/LRR-ω-γ uses simplified correlations that do not depend on freestream quantities, making it coordinate independent and rendering it Galilean invariant. Additionally, using a second-order closure turbulence model makes it suitable for complex flow fields. The influence of different grid parameters on the model is also discussed. A validation study is performed using multiple benchmark flat plate cases as well as 2D and 3D geometries to demonstrate the model's capability in predicting different transition mechanisms. When compared to state-of-the-art transition models, the proposed model shows equivalent or higher predictive capability.
{"title":"Reynolds Stress Turbulence Modelling with γ Transition Model","authors":"Naina Pisharoti, J. Webster, S. Brizzolara","doi":"10.1080/10618562.2022.2070614","DOIUrl":"https://doi.org/10.1080/10618562.2022.2070614","url":null,"abstract":"Implementation of the SSG/LRR-ω-γ model is carried out in the current study to predict transition to turbulence. The framework uses a Reynolds stress transport model, SSG/LRR-ω, as the base turbulence formulation and is coupled with Menter's γ transition model. To extend its applicability to different transition mechanisms, the production terms in the Reynolds stress and specific dissipation rate transport equations are modified. SSG/LRR-ω-γ uses simplified correlations that do not depend on freestream quantities, making it coordinate independent and rendering it Galilean invariant. Additionally, using a second-order closure turbulence model makes it suitable for complex flow fields. The influence of different grid parameters on the model is also discussed. A validation study is performed using multiple benchmark flat plate cases as well as 2D and 3D geometries to demonstrate the model's capability in predicting different transition mechanisms. When compared to state-of-the-art transition models, the proposed model shows equivalent or higher predictive capability.","PeriodicalId":56288,"journal":{"name":"International Journal of Computational Fluid Dynamics","volume":"37 1","pages":"21 - 43"},"PeriodicalIF":1.3,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81789431","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}
Pub Date : 2022-01-02DOI: 10.1080/10618562.2022.2087873
D. Rizzetta, D. Garmann
Wall-resolved large-eddy simulations were carried out for flow over a rearward-facing ramp configuration, which is representative of surfaces generating smooth-body separation. The geometry and flow conditions were motivated by an experimental investigation, which was conducted in order to provide data for validating numerical modelling. Because the experimental Reynolds number is challenging, even for approximate techniques, the present computations were initiated in order to provide benchmark results for a comparison of numerical methods. Solutions to the unsteady three-dimensional compressible Navier-Stokes equations were obtained utilising a high-fidelity computational scheme and an implicit time-marching approach. Grid resolution studies were performed to assure numerical accuracy. A number of metrics are indicated that attest to quality of the solutions. Features of the flowfields are elucidated, and comparisons are made between results at two different Reynolds numbers. A description of boundary-layer parameters and development of turbulence along the ramp surface are also provided.
{"title":"Wall-Resolved Large-Eddy Simulation of Smooth-Body Separated Flow","authors":"D. Rizzetta, D. Garmann","doi":"10.1080/10618562.2022.2087873","DOIUrl":"https://doi.org/10.1080/10618562.2022.2087873","url":null,"abstract":"Wall-resolved large-eddy simulations were carried out for flow over a rearward-facing ramp configuration, which is representative of surfaces generating smooth-body separation. The geometry and flow conditions were motivated by an experimental investigation, which was conducted in order to provide data for validating numerical modelling. Because the experimental Reynolds number is challenging, even for approximate techniques, the present computations were initiated in order to provide benchmark results for a comparison of numerical methods. Solutions to the unsteady three-dimensional compressible Navier-Stokes equations were obtained utilising a high-fidelity computational scheme and an implicit time-marching approach. Grid resolution studies were performed to assure numerical accuracy. A number of metrics are indicated that attest to quality of the solutions. Features of the flowfields are elucidated, and comparisons are made between results at two different Reynolds numbers. A description of boundary-layer parameters and development of turbulence along the ramp surface are also provided.","PeriodicalId":56288,"journal":{"name":"International Journal of Computational Fluid Dynamics","volume":"69 1","pages":"1 - 20"},"PeriodicalIF":1.3,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78133387","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}
Pub Date : 2022-01-02DOI: 10.1080/10618562.2022.2053114
Z. Shahraki, M. Navidbakhsh, Robert A. Taylor
In the field of microfluidic inertial-based focusing of suspended particles, no research has been conducted to bring together two of the main directions of research, trapezoid spiral microchannels and contraction-expansion array (CEA)s. This paper addresses that gap by investigating two proposed CEAs (smooth and abrupt) inside a spiral channel compared to a uniform cross-section design at three different flow rates (i.e. 3, 6, and . The conservation equations of mass and momentum with a Lagrangian’-Eulerian (LE) approach are solved in OpenFOAM, using a four-way coupling between the phases. The results indicate that adding smooth transition CEAs to spiral microchannels, at a nominal flow rate , decreases the focusing duration (by about 29%) and the cell lysis probability (by about 52%) while keeping the separation efficiency high (nearly 100%). Overall, this study opens a promising new, integrated direction for passive microfluidic focusing of particles.
{"title":"Coupling Contraction-expansion Arrays with Spiral Microchannels to Enhance Microfluidic-Based Particle/Cell Separation","authors":"Z. Shahraki, M. Navidbakhsh, Robert A. Taylor","doi":"10.1080/10618562.2022.2053114","DOIUrl":"https://doi.org/10.1080/10618562.2022.2053114","url":null,"abstract":"In the field of microfluidic inertial-based focusing of suspended particles, no research has been conducted to bring together two of the main directions of research, trapezoid spiral microchannels and contraction-expansion array (CEA)s. This paper addresses that gap by investigating two proposed CEAs (smooth and abrupt) inside a spiral channel compared to a uniform cross-section design at three different flow rates (i.e. 3, 6, and . The conservation equations of mass and momentum with a Lagrangian’-Eulerian (LE) approach are solved in OpenFOAM, using a four-way coupling between the phases. The results indicate that adding smooth transition CEAs to spiral microchannels, at a nominal flow rate , decreases the focusing duration (by about 29%) and the cell lysis probability (by about 52%) while keeping the separation efficiency high (nearly 100%). Overall, this study opens a promising new, integrated direction for passive microfluidic focusing of particles.","PeriodicalId":56288,"journal":{"name":"International Journal of Computational Fluid Dynamics","volume":"27 1","pages":"63 - 90"},"PeriodicalIF":1.3,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77565450","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}
A mathematical model for the creeping micropolar flow past a porous oblate spheroidal body is presented. The oblate spheroidal body possesses permeability k and uniform stream velocity is assumed far away from the body and along its axis of symmetry. The flow inside the particle obeys the DarcyBrinkman laws of porosity and the fluid outside is governed by the A.C. Eringen micropolar flow theory. Drag is determined with varying values of the permeability parameter η and the coupling number N . Also, the micropolar parameter m is studied numerically.
{"title":"Creeping Micropolar Flow past a Porous Oblate Spheroid","authors":"A. R., Rahaman K, Comissiong Dmg","doi":"10.36959/717/660","DOIUrl":"https://doi.org/10.36959/717/660","url":null,"abstract":"A mathematical model for the creeping micropolar flow past a porous oblate spheroidal body is presented. The oblate spheroidal body possesses permeability k and uniform stream velocity is assumed far away from the body and along its axis of symmetry. The flow inside the particle obeys the DarcyBrinkman laws of porosity and the fluid outside is governed by the A.C. Eringen micropolar flow theory. Drag is determined with varying values of the permeability parameter η and the coupling number N . Also, the micropolar parameter m is studied numerically.","PeriodicalId":56288,"journal":{"name":"International Journal of Computational Fluid Dynamics","volume":"34 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82718454","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}
{"title":"The Effect of Nanoparticles on MHD Blood Flow in Stretching Arterial Porous Vessel with the Influence of Thermal Radiation, Chemical Reaction and Heat Generation/Absorption","authors":"Zigta Binyam","doi":"10.36959/717/659","DOIUrl":"https://doi.org/10.36959/717/659","url":null,"abstract":"","PeriodicalId":56288,"journal":{"name":"International Journal of Computational Fluid Dynamics","volume":"361 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78909454","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}
Pub Date : 2021-11-26DOI: 10.1080/10618562.2022.2052280
Manokaran Krishnamurthy, R. Mokkapati, Jayachandran Thankappan
A circular cylinder placed in a uniform flow with its axis perpendicular to the flow direction can result in an unsteady flow caused by vortex shedding. Numerical simulations attempting to capture this phenomenon may lack a trigger to cause the appropriate vortex shedding, consequently, asymmetric vortex shedding can be delayed or may not occur. Therefore, an artificial disturbance can be introduced into the flow field to initiate an earlier onset of vortex shedding. Here, the wall boundary condition is used to perturb the local shear layer. It is tested for a circular cylinder at Reynolds numbers of 40, 60 and 150. Application of wall perturbation technique triggers the onset of asymmetrical vortex shedding and in the absence of a perturbation, asymmetrical vortex shedding does not occur. The effect of the patch size and duration of application of initial perturbation on the onset of vortex shedding for Re = 150 is reported.
{"title":"Perturbation of Wall Boundary Condition to Trigger Vortex Shedding Over a Circular Cylinder","authors":"Manokaran Krishnamurthy, R. Mokkapati, Jayachandran Thankappan","doi":"10.1080/10618562.2022.2052280","DOIUrl":"https://doi.org/10.1080/10618562.2022.2052280","url":null,"abstract":"A circular cylinder placed in a uniform flow with its axis perpendicular to the flow direction can result in an unsteady flow caused by vortex shedding. Numerical simulations attempting to capture this phenomenon may lack a trigger to cause the appropriate vortex shedding, consequently, asymmetric vortex shedding can be delayed or may not occur. Therefore, an artificial disturbance can be introduced into the flow field to initiate an earlier onset of vortex shedding. Here, the wall boundary condition is used to perturb the local shear layer. It is tested for a circular cylinder at Reynolds numbers of 40, 60 and 150. Application of wall perturbation technique triggers the onset of asymmetrical vortex shedding and in the absence of a perturbation, asymmetrical vortex shedding does not occur. The effect of the patch size and duration of application of initial perturbation on the onset of vortex shedding for Re = 150 is reported.","PeriodicalId":56288,"journal":{"name":"International Journal of Computational Fluid Dynamics","volume":"7 1","pages":"872 - 892"},"PeriodicalIF":1.3,"publicationDate":"2021-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87496178","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}
Pub Date : 2021-11-26DOI: 10.1080/10618562.2021.2019226
J. Benhamou, S. Channouf, M. Jami, A. Mezrhab, D. Henry, V. Botton
This paper implements the lattice Boltzmann method to simulate the propagation of sound waves in three dimensions. The numerical model is exercised on the lid-driven cavity flow. Tests are then proposed on acoustic situations. The results are first confronted with analytical solutions of the spherical waves emitted by a single point source inside a cubic cavity. Then, we studied the case where the waves are emitted from a circular sound source placed at the center of the left boundary of a parallelepipedic cavity filled with water. With the circular source discretized as a set of point sources, we were able to simulate the wave propagation in 3D and calculate the sound pressure amplitude. Tests using different emission conditions and LBM relaxation times finally allowed us to get good comparisons with analytical expressions of the pressure amplitude along the source axis, highlighting the performance of the lattice Boltzmann simulations in acoustics.
{"title":"Three-Dimensional Lattice Boltzmann Model for Acoustic Waves Emitted by a Source","authors":"J. Benhamou, S. Channouf, M. Jami, A. Mezrhab, D. Henry, V. Botton","doi":"10.1080/10618562.2021.2019226","DOIUrl":"https://doi.org/10.1080/10618562.2021.2019226","url":null,"abstract":"This paper implements the lattice Boltzmann method to simulate the propagation of sound waves in three dimensions. The numerical model is exercised on the lid-driven cavity flow. Tests are then proposed on acoustic situations. The results are first confronted with analytical solutions of the spherical waves emitted by a single point source inside a cubic cavity. Then, we studied the case where the waves are emitted from a circular sound source placed at the center of the left boundary of a parallelepipedic cavity filled with water. With the circular source discretized as a set of point sources, we were able to simulate the wave propagation in 3D and calculate the sound pressure amplitude. Tests using different emission conditions and LBM relaxation times finally allowed us to get good comparisons with analytical expressions of the pressure amplitude along the source axis, highlighting the performance of the lattice Boltzmann simulations in acoustics.","PeriodicalId":56288,"journal":{"name":"International Journal of Computational Fluid Dynamics","volume":"35 1","pages":"850 - 871"},"PeriodicalIF":1.3,"publicationDate":"2021-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80067287","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：