Pub Date : 2024-12-04DOI: 10.1016/j.compfluid.2024.106506
Davide Oberto , Davide Fransos , Stefano Berrone
Despite the emerging field of data-driven turbulence models, there is a lack of systematic high-fidelity datasets at flow configurations changing continuously with respect to geometrical/physical parameters. In this work, we investigate the possibility of using Delayed Detached Eddy Simulation (DDES) to generate reliable datasets in a significantly cheaper manner compared to the DNS or LES counterparts. To do that, we perform 25 simulations of the geometrically-parameterized periodic hills test case to deal with different hills steepnesses. We firstly check the accuracy of our results by comparing one simulation with the benchmark case of Xiao et al. Then, we use such database to train the turbulent viscosity-Vector Basis Neural Network (-VBNN) data-driven turbulence model. The latter outperforms the classic SST RANS model, proving that our generated dataset can be useful for data-driven turbulence modeling and opening the opportunity to exploit DDES to create systematic datasets for data-driven turbulence modeling.
{"title":"Using Delayed Detached Eddy Simulation to create datasets for data-driven turbulence modeling: A periodic hills with parameterized geometry case","authors":"Davide Oberto , Davide Fransos , Stefano Berrone","doi":"10.1016/j.compfluid.2024.106506","DOIUrl":"10.1016/j.compfluid.2024.106506","url":null,"abstract":"<div><div>Despite the emerging field of data-driven turbulence models, there is a lack of systematic high-fidelity datasets at flow configurations changing continuously with respect to geometrical/physical parameters. In this work, we investigate the possibility of using Delayed Detached Eddy Simulation (DDES) to generate reliable datasets in a significantly cheaper manner compared to the DNS or LES counterparts. To do that, we perform 25 simulations of the geometrically-parameterized periodic hills test case to deal with different hills steepnesses. We firstly check the accuracy of our results by comparing one simulation with the benchmark case of Xiao et al. Then, we use such database to train the turbulent viscosity-Vector Basis Neural Network (<span><math><msub><mrow><mi>ν</mi></mrow><mrow><mi>t</mi></mrow></msub></math></span>-VBNN) data-driven turbulence model. The latter outperforms the classic <span><math><mrow><mi>k</mi><mo>−</mo><mi>ω</mi></mrow></math></span> SST RANS model, proving that our generated dataset can be useful for data-driven turbulence modeling and opening the opportunity to exploit DDES to create systematic datasets for data-driven turbulence modeling.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"288 ","pages":"Article 106506"},"PeriodicalIF":2.5,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143138731","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}
Pub Date : 2024-12-02DOI: 10.1016/j.compfluid.2024.106498
Ludovico Nista , Christoph D.K. Schumann , Peicho Petkov , Valentin Pavlov , Temistocle Grenga , Jonathan F. MacArt , Antonio Attili , Stoyan Markov , Heinz Pitsch
Super-resolution (SR) generative adversarial networks (GANs) are promising for turbulence closure in large-eddy simulation (LES) due to their ability to accurately reconstruct high-resolution data from low-resolution fields. Current model training and inference strategies are not sufficiently mature for large-scale, distributed calculations due to the computational demands and often unstable training of SR-GANs, which limits the exploration of improved model structures, training strategies, and loss-function definitions. Integrating SR-GANs into LES solvers for inference-coupled simulations is also necessary to assess their a posteriori accuracy, stability, and cost. We investigate parallelization strategies for SR-GAN training and inference-coupled LES, focusing on computational performance and reconstruction accuracy. We examine distributed data-parallel training strategies for hybrid CPU–GPU node architectures and the associated influence of low-/high-resolution subbox size, global batch size, and discriminator accuracy. Accurate predictions require training subboxes that are sufficiently large relative to the Kolmogorov length scale. Care should be placed on the coupled effect of training batch size, learning rate, number of training subboxes, and discriminator’s learning capabilities. We introduce a data-parallel SR-GAN training and inference library for heterogeneous architectures that enables exchange between the LES solver and SR-GAN inference at runtime. We investigate the predictive accuracy and computational performance of this arrangement with particular focus on the overlap (halo) size required for accurate SR reconstruction. Similarly, a posteriori parallel scaling for efficient inference-coupled LES is constrained by the SR subdomain size, GPU utilization, and reconstruction accuracy. Based on these findings, we establish guidelines and best practices to optimize resource utilization and parallel acceleration of SR-GAN turbulence model training and inference-coupled LES calculations while maintaining predictive accuracy.
{"title":"Parallel implementation and performance of super-resolution generative adversarial network turbulence models for large-eddy simulation","authors":"Ludovico Nista , Christoph D.K. Schumann , Peicho Petkov , Valentin Pavlov , Temistocle Grenga , Jonathan F. MacArt , Antonio Attili , Stoyan Markov , Heinz Pitsch","doi":"10.1016/j.compfluid.2024.106498","DOIUrl":"10.1016/j.compfluid.2024.106498","url":null,"abstract":"<div><div>Super-resolution (SR) generative adversarial networks (GANs) are promising for turbulence closure in large-eddy simulation (LES) due to their ability to accurately reconstruct high-resolution data from low-resolution fields. Current model training and inference strategies are not sufficiently mature for large-scale, distributed calculations due to the computational demands and often unstable training of SR-GANs, which limits the exploration of improved model structures, training strategies, and loss-function definitions. Integrating SR-GANs into LES solvers for inference-coupled simulations is also necessary to assess their <em>a posteriori</em> accuracy, stability, and cost. We investigate parallelization strategies for SR-GAN training and inference-coupled LES, focusing on computational performance and reconstruction accuracy. We examine distributed data-parallel training strategies for hybrid CPU–GPU node architectures and the associated influence of low-/high-resolution subbox size, global batch size, and discriminator accuracy. Accurate predictions require training subboxes that are sufficiently large relative to the Kolmogorov length scale. Care should be placed on the coupled effect of training batch size, learning rate, number of training subboxes, and discriminator’s learning capabilities. We introduce a data-parallel SR-GAN training and inference library for heterogeneous architectures that enables exchange between the LES solver and SR-GAN inference at runtime. We investigate the predictive accuracy and computational performance of this arrangement with particular focus on the overlap (halo) size required for accurate SR reconstruction. Similarly, <em>a posteriori</em> parallel scaling for efficient inference-coupled LES is constrained by the SR subdomain size, GPU utilization, and reconstruction accuracy. Based on these findings, we establish guidelines and best practices to optimize resource utilization and parallel acceleration of SR-GAN turbulence model training and inference-coupled LES calculations while maintaining predictive accuracy.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"288 ","pages":"Article 106498"},"PeriodicalIF":2.5,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143138560","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}
Pub Date : 2024-11-30DOI: 10.1016/j.compfluid.2024.106497
Dandan Wang , Yu-xin Ren , Mengnan Ding
Large eddy simulation (LES) of two-dimensional (2D) turbulence is often used in the geostrophic flows. However, some basic dynamics underlying traditional SGS models are absent in 2D turbulence, e.g. the vortex stretching. Hence, this research proposes an optimized dynamic similarity model (DSM) for the SGS stress, which is constructed through the dynamic procedure based on the Germano identity. In addition, a modification is made to the dynamic mixed model (DMM) for the sake of realizability condition. The optimized DSM is justified in comparison with the DMM, through the a priori and a posteriori verifications, in the context of the 2D decaying turbulence with turbulent Reynolds number of and turbulent Mach number of . Special attention is paid to the consistency of the verification procedure, so that the filtering operations used in the direct numerical simulation (DNS) and LES are optimally equivalent. The SGS transport phenomena, especially the SGS backscatter, predicted by these two models are studied in detail. In addition, the optimized DSM and the DMM are extended for the modified SGS transport vectors of passive scalars to show their capability in calculating 2D turbulent mixing. The numerical results show the optimized DSM provides larger correlation coefficient, better locality, and stronger SGS backscsatter than the DMM does, and therefore it is more suitable for the LES of 2D turbulence.
{"title":"Optimized dynamic similarity models to predict SGS backscatter in 2D decaying turbulence","authors":"Dandan Wang , Yu-xin Ren , Mengnan Ding","doi":"10.1016/j.compfluid.2024.106497","DOIUrl":"10.1016/j.compfluid.2024.106497","url":null,"abstract":"<div><div>Large eddy simulation (LES) of two-dimensional (2D) turbulence is often used in the geostrophic flows. However, some basic dynamics underlying traditional SGS models are absent in 2D turbulence, e.g. the vortex stretching. Hence, this research proposes an optimized dynamic similarity model (DSM) for the SGS stress, which is constructed through the dynamic procedure based on the Germano identity. In addition, a modification is made to the dynamic mixed model (DMM) for the sake of realizability condition. The optimized DSM is justified in comparison with the DMM, through the a priori and a posteriori verifications, in the context of the 2D decaying turbulence with turbulent Reynolds number of <span><math><mrow><mi>R</mi><mi>e</mi><mo>=</mo><mn>3</mn><mo>.</mo><mn>7</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>4</mn></mrow></msup></mrow></math></span> and turbulent Mach number of <span><math><mrow><msub><mrow><mi>M</mi></mrow><mrow><mi>t</mi></mrow></msub><mo>=</mo><mn>0</mn><mo>.</mo><mn>1</mn></mrow></math></span>. Special attention is paid to the consistency of the verification procedure, so that the filtering operations used in the direct numerical simulation (DNS) and LES are optimally equivalent. The SGS transport phenomena, especially the SGS backscatter, predicted by these two models are studied in detail. In addition, the optimized DSM and the DMM are extended for the modified SGS transport vectors of passive scalars to show their capability in calculating 2D turbulent mixing. The numerical results show the optimized DSM provides larger correlation coefficient, better locality, and stronger SGS backscsatter than the DMM does, and therefore it is more suitable for the LES of 2D turbulence.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"288 ","pages":"Article 106497"},"PeriodicalIF":2.5,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143138562","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}
Pub Date : 2024-11-30DOI: 10.1016/j.compfluid.2024.106496
Silvia Ceccacci , Sophie A.W. Calabretto , Christian Thomas , James P. Denier
The effect of surface slip on the dynamics of flow separation induced by a Gaussian-shaped gap deformity in a two-dimensional channel was numerically investigated for Reynolds numbers . Two gap deformations, denoted wide and narrow, were modelled with dimensions sufficient to generate localised pockets of reversed flow when the channel walls were fully no-slip. The wide gap induces a more intense region of separated flow than the narrow gap but less than that exhibited by similar-sized bumps in a channel (Ceccacci et al., 2022). In addition, the size and magnitude of the separation bubble within each gap deformity plateaued for Reynolds numbers . Surface slip with slip length, , was modelled via a Navier-slip boundary condition. Applying the slip condition to the gap concavity reduces the magnitude and thickness of the separation bubble within the deformation and, for a slip length , eliminates separated flow for both gap configurations, which is less than the requirements for the bump configuration (Ceccacci et al., 2022). Moreover, limiting slip to the gap region, achieved the same flow separation control, as that realised by applying slip to the entire wall.
{"title":"Direct numerical simulations of two-dimensional channel flow with a gap deformity and slip wall","authors":"Silvia Ceccacci , Sophie A.W. Calabretto , Christian Thomas , James P. Denier","doi":"10.1016/j.compfluid.2024.106496","DOIUrl":"10.1016/j.compfluid.2024.106496","url":null,"abstract":"<div><div>The effect of surface slip on the dynamics of flow separation induced by a Gaussian-shaped gap deformity in a two-dimensional channel was numerically investigated for Reynolds numbers <span><math><mrow><mi>Re</mi><mo>∈</mo><mrow><mo>[</mo><mn>100</mn><mo>,</mo><mn>6000</mn><mo>]</mo></mrow></mrow></math></span>. Two gap deformations, denoted wide and narrow, were modelled with dimensions sufficient to generate localised pockets of reversed flow when the channel walls were fully no-slip. The wide gap induces a more intense region of separated flow than the narrow gap but less than that exhibited by similar-sized bumps in a channel (Ceccacci et al., 2022). In addition, the size and magnitude of the separation bubble within each gap deformity plateaued for Reynolds numbers <span><math><mrow><mi>Re</mi><mo>></mo><mn>3000</mn></mrow></math></span>. Surface slip with slip length, <span><math><mi>λ</mi></math></span>, was modelled via a Navier-slip boundary condition. Applying the slip condition to the gap concavity reduces the magnitude and thickness of the separation bubble within the deformation and, for a slip length <span><math><mrow><mi>λ</mi><mo>≈</mo><mn>0</mn><mo>.</mo><mn>1</mn></mrow></math></span>, eliminates separated flow for both gap configurations, which is less than the requirements for the bump configuration (Ceccacci et al., 2022). Moreover, limiting slip to the gap region, achieved the same flow separation control, as that realised by applying slip to the entire wall.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"288 ","pages":"Article 106496"},"PeriodicalIF":2.5,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143138729","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}
Pub Date : 2024-11-30DOI: 10.1016/j.compfluid.2024.106471
A. Zijian Mao (毛子鉴) , B. Shuiqing Zhou (周水清) , C. Tianle Zhang (张天乐) , D. Jiacheng He (何嘉成) , E. Weiya Jin (金伟娅) , F. Weiping Feng (冯伟平)
Unlike centrifugal fans, diagonal flow fans have an air inflow direction at a certain angle to the axis, with tip clearance (TC) significantly affecting aerodynamic performance and noise. This study focuses on investigating the effects of four different TC shapes based on blade height (BH) ratios. Large Eddy Simulation (LES) was used to capture the structure and development of tip leakage flow (TLF) and tip leakage vortex (TLV) accurately. Diagonal flow fan casings with different TC shapes were 3D-printed for aerodynamic performance experiments. The results from both numerical simulations and experiments show that diagonal flow fans with Tapering or Parallel TC shapes achieve superior aerodynamic performance compared to other geometries, with a 24.1% variance in flow rate. The study further indicates that different TC shapes significantly influence the flow field, altering the mechanisms governing turbulence transition on the suction side. Compared to the Diverging shape, reducing the TC width decreases the amplitude of the TLV, which in turn reduces the turbulence-affected area while increasing dominant mode frequencies. Experimental results also confirm that the Tapering-Diverging TC shape yields the lowest noise levels, with a 3.6 dB reduction in Sound Pressure Level (SPL).
{"title":"Investigation of aerodynamic performance and noise of tip shape clearance in a diagonal flow fan","authors":"A. Zijian Mao (毛子鉴) , B. Shuiqing Zhou (周水清) , C. Tianle Zhang (张天乐) , D. Jiacheng He (何嘉成) , E. Weiya Jin (金伟娅) , F. Weiping Feng (冯伟平)","doi":"10.1016/j.compfluid.2024.106471","DOIUrl":"10.1016/j.compfluid.2024.106471","url":null,"abstract":"<div><div>Unlike centrifugal fans, diagonal flow fans have an air inflow direction at a certain angle to the axis, with tip clearance (TC) significantly affecting aerodynamic performance and noise. This study focuses on investigating the effects of four different TC shapes based on blade height (BH) ratios. Large Eddy Simulation (LES) was used to capture the structure and development of tip leakage flow (TLF) and tip leakage vortex (TLV) accurately. Diagonal flow fan casings with different TC shapes were 3D-printed for aerodynamic performance experiments. The results from both numerical simulations and experiments show that diagonal flow fans with Tapering or Parallel TC shapes achieve superior aerodynamic performance compared to other geometries, with a 24.1% variance in flow rate. The study further indicates that different TC shapes significantly influence the flow field, altering the mechanisms governing turbulence transition on the suction side. Compared to the Diverging shape, reducing the TC width decreases the amplitude of the TLV, which in turn reduces the turbulence-affected area while increasing dominant mode frequencies. Experimental results also confirm that the Tapering-Diverging TC shape yields the lowest noise levels, with a 3.6 dB reduction in Sound Pressure Level (SPL).</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"288 ","pages":"Article 106471"},"PeriodicalIF":2.5,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143138564","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}
Pub Date : 2024-11-28DOI: 10.1016/j.compfluid.2024.106494
Jun Seok Oh , Tae Yoon Kung , Kyu Hong Kim
In this paper, we develop a novel search-based wall distance calculation algorithm. The algorithm is highly efficient and satisfies the crucial requirement of exactness in wall distance calculations, taking into account the full geometry of the discretized surface. Unlike conventional search-based algorithms that use element-wise bounding boxes or auxiliary grids, the developed algorithm employs only a set of zero-dimensional reference points representing the elements of the discretized surface. Reference points can be chosen as the centers of faces, the centers of edges, or the vertices. The conservative relation between the approximate distance using one of these references and the exact distance is established, allowing for the efficient extraction of element candidates using only low-level information. The algorithm does not require complex pre-processing of the surface or any information about the query points, ensuring high software modularity. An intuitive load balancing procedure is also proposed to address the load imbalance arising from partitioning-based parallelization. Numerical test demonstrates that the developed algorithm shows three orders of magnitude speed-up compared to exhaustive search and one to two orders of magnitude speed-up compared to other search-based algorithms. It also shows high parallel scalability on partitioned meshes, indicating its feasibility for large-scale problems.
{"title":"Exact and efficient search-based wall distance algorithm for partitioned unstructured grids","authors":"Jun Seok Oh , Tae Yoon Kung , Kyu Hong Kim","doi":"10.1016/j.compfluid.2024.106494","DOIUrl":"10.1016/j.compfluid.2024.106494","url":null,"abstract":"<div><div>In this paper, we develop a novel search-based wall distance calculation algorithm. The algorithm is highly efficient and satisfies the crucial requirement of exactness in wall distance calculations, taking into account the full geometry of the discretized surface. Unlike conventional search-based algorithms that use element-wise bounding boxes or auxiliary grids, the developed algorithm employs only a set of zero-dimensional reference points representing the elements of the discretized surface. Reference points can be chosen as the centers of faces, the centers of edges, or the vertices. The conservative relation between the approximate distance using one of these references and the exact distance is established, allowing for the efficient extraction of element candidates using only low-level information. The algorithm does not require complex pre-processing of the surface or any information about the query points, ensuring high software modularity. An intuitive load balancing procedure is also proposed to address the load imbalance arising from partitioning-based parallelization. Numerical test demonstrates that the developed algorithm shows three orders of magnitude speed-up compared to exhaustive search and one to two orders of magnitude speed-up compared to other search-based algorithms. It also shows high parallel scalability on partitioned meshes, indicating its feasibility for large-scale problems.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"288 ","pages":"Article 106494"},"PeriodicalIF":2.5,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143138567","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}
Pub Date : 2024-11-26DOI: 10.1016/j.compfluid.2024.106477
André F.P. Ribeiro , Thomas Leweke , Aliza Abraham , Jens N. Sørensen , Robert F. Mikkelsen
This work concerns high-fidelity numerical simulations of a rotor wake, with focus on the tip vortices and their stability. Blade-resolved and actuator line lattice-Boltzmann simulations are performed on a symmetric baseline rotor, as well as on a rotor with asymmetries. The asymmetry has the purpose of destabilizing the tip vortices to enhance wake recovery and hence the performance of potential downstream turbines. Limitations in the actuator line method are highlighted, and we show the potential of addressing these limitations with a so-called “preset” actuator line, where the forces are extracted from blade-resolved simulations, or an analytical load model, which as input only requires the thrust and power coefficients. Simulations agree well with experimental results and leapfrogging is captured, even with a coarse actuator line simulation. The asymmetric rotor is shown to improve power in the far-wake by 12%.
{"title":"Blade-resolved and actuator line simulations of rotor wakes","authors":"André F.P. Ribeiro , Thomas Leweke , Aliza Abraham , Jens N. Sørensen , Robert F. Mikkelsen","doi":"10.1016/j.compfluid.2024.106477","DOIUrl":"10.1016/j.compfluid.2024.106477","url":null,"abstract":"<div><div>This work concerns high-fidelity numerical simulations of a rotor wake, with focus on the tip vortices and their stability. Blade-resolved and actuator line lattice-Boltzmann simulations are performed on a symmetric baseline rotor, as well as on a rotor with asymmetries. The asymmetry has the purpose of destabilizing the tip vortices to enhance wake recovery and hence the performance of potential downstream turbines. Limitations in the actuator line method are highlighted, and we show the potential of addressing these limitations with a so-called “preset” actuator line, where the forces are extracted from blade-resolved simulations, or an analytical load model, which as input only requires the thrust and power coefficients. Simulations agree well with experimental results and leapfrogging is captured, even with a coarse actuator line simulation. The asymmetric rotor is shown to improve power in the far-wake by 12%.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"287 ","pages":"Article 106477"},"PeriodicalIF":2.5,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142744110","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}
Pub Date : 2024-11-26DOI: 10.1016/j.compfluid.2024.106493
Jean-Luc Guermond , Matthias Maier , Eric J. Tovar
We introduce a high-order space–time approximation of the Shallow Water Equations with sources that is invariant-domain preserving (IDP), well-balanced with respect to rest states, and employs a novel explicit Runge–Kutta (ERK) introduced in Ern and Guermond (SIAM J. Sci. Comput. 44(5), A3366–A3392, 2022) for systems of non-linear conservation equations. The resulting method is then numerically illustrated through verification and validation.
{"title":"A high-order explicit Runge-Kutta approximation technique for the shallow water equations","authors":"Jean-Luc Guermond , Matthias Maier , Eric J. Tovar","doi":"10.1016/j.compfluid.2024.106493","DOIUrl":"10.1016/j.compfluid.2024.106493","url":null,"abstract":"<div><div>We introduce a high-order space–time approximation of the Shallow Water Equations with sources that is invariant-domain preserving (IDP), well-balanced with respect to rest states, and employs a novel explicit Runge–Kutta (ERK) introduced in Ern and Guermond (SIAM J. Sci. Comput. 44(5), A3366–A3392, 2022) for systems of non-linear conservation equations. The resulting method is then numerically illustrated through verification and validation.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"288 ","pages":"Article 106493"},"PeriodicalIF":2.5,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143138561","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}
Pub Date : 2024-11-22DOI: 10.1016/j.compfluid.2024.106489
Yanguang Yang, Ming Fang, Weidong Li, Zhaoli Guo, Manfred Krafczyk, Li-Shi Luo
{"title":"Computers and fluids special issue “Mesoscopic methods and their applications to CFD”","authors":"Yanguang Yang, Ming Fang, Weidong Li, Zhaoli Guo, Manfred Krafczyk, Li-Shi Luo","doi":"10.1016/j.compfluid.2024.106489","DOIUrl":"10.1016/j.compfluid.2024.106489","url":null,"abstract":"","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"286 ","pages":"Article 106489"},"PeriodicalIF":2.5,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142756722","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}
Pub Date : 2024-11-19DOI: 10.1016/j.compfluid.2024.106491
Xiaoyang Xu, Wei Yu
In this paper, an improved smoothed particle hydrodynamics (SPH) method is employed to accurately simulate non-isothermal viscoplastic free surface flows, wherein the viscoplastic behavior of the fluid is precisely captured through the incorporation of the Herschel-Bulkley-Papanastasiou constitutive model. To suppress the non-physical oscillation arising from the weakly compressible hypothesis within the pressure field, the density dissipation term is incorporated into the mass conservation equation. To address the tensile instability arising from the uneven distribution of particles, the particle shifting technique is incorporated as a solution. To enhance the precision and ensure numerical stability of the gradient operator, a kernel gradient correction algorithm is implemented. The improved SPH method is employed for numerically simulating the non-isothermal viscoplastic mixed convection, dam-break flow and droplet impacting the solid wall. The effectiveness of the improved SPH method in tackling the complexities of non-isothermal viscoplastic fluid is validated through a rigorous comparison of its outcomes with those derived from alternative numerical methodologies. The assessment of the numerical convergence of the improved SPH method is undertaken through the utilization of varying initial particle spacings. The numerical outcomes demonstrate that the improved SPH method adeptly and precisely delineates the heat transfer mechanisms, intricate rheological properties, as well as the dynamic variation characteristics of the free surface in non-isothermal viscoplastic free surface flows.
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