Computers & Fluids最新文献_第8页

Optimized dynamic similarity models to predict SGS backscatter in 2D decaying turbulence

IF 2.5 3区工程技术 SCI

Computers & Fluids Pub Date : 2024-11-30 DOI: 10.1016/j.compfluid.2024.106497

Dandan Wang , Yu-xin Ren , Mengnan Ding

{"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}

引用次数: 0

Direct numerical simulations of two-dimensional channel flow with a gap deformity and slip wall

IF 2.5 3区工程技术 SCI

Computers & Fluids Pub Date : 2024-11-30 DOI: 10.1016/j.compfluid.2024.106496

Silvia Ceccacci , Sophie A.W. Calabretto , Christian Thomas , James P. Denier

{"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}

引用次数: 0

Investigation of aerodynamic performance and noise of tip shape clearance in a diagonal flow fan

IF 2.5 3区工程技术 SCI

Computers & Fluids Pub Date : 2024-11-30 DOI: 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)

{"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}

引用次数: 0

Exact and efficient search-based wall distance algorithm for partitioned unstructured grids

IF 2.5 3区工程技术 SCI

Computers & Fluids Pub Date : 2024-11-28 DOI: 10.1016/j.compfluid.2024.106494

Jun Seok Oh , Tae Yoon Kung , Kyu Hong Kim

{"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}

引用次数: 0

Blade-resolved and actuator line simulations of rotor wakes 旋翼尾迹的叶片解析和致动器线仿真

IF 2.5 3区工程技术 SCI

Computers & Fluids Pub Date : 2024-11-26 DOI: 10.1016/j.compfluid.2024.106477

André F.P. Ribeiro , Thomas Leweke , Aliza Abraham , Jens N. Sørensen , Robert F. Mikkelsen

引用次数: 0

A high-order explicit Runge-Kutta approximation technique for the shallow water equations

IF 2.5 3区工程技术 SCI

Computers & Fluids Pub Date : 2024-11-26 DOI: 10.1016/j.compfluid.2024.106493

Jean-Luc Guermond , Matthias Maier , Eric J. Tovar

引用次数: 0

Computers and fluids special issue “Mesoscopic methods and their applications to CFD” 计算机与流体专刊“介观方法及其在CFD中的应用”

IF 2.5 3区工程技术 SCI

Computers & Fluids Pub Date : 2024-11-22 DOI: 10.1016/j.compfluid.2024.106489

Yanguang Yang, Ming Fang, Weidong Li, Zhaoli Guo, Manfred Krafczyk, Li-Shi Luo

引用次数: 0

SPH simulations of non-isothermal viscoplastic free-surface flows incorporating Herschel-Bulkley-Papanastasiou model 结合 Herschel-Bulkley-Papanastasiou 模型的非等温粘塑性自由表面流的 SPH 模拟

IF 2.5 3区工程技术 SCI

Computers & Fluids Pub Date : 2024-11-19 DOI: 10.1016/j.compfluid.2024.106491

Xiaoyang Xu, Wei Yu

{"title":"SPH simulations of non-isothermal viscoplastic free-surface flows incorporating Herschel-Bulkley-Papanastasiou model","authors":"Xiaoyang Xu, Wei Yu","doi":"10.1016/j.compfluid.2024.106491","DOIUrl":"10.1016/j.compfluid.2024.106491","url":null,"abstract":"<div><div>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.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"287 ","pages":"Article 106491"},"PeriodicalIF":2.5,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142702762","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}

引用次数: 0

High-order gas kinetic flux solver with TENO-THINC scheme for compressible flows 采用 TENO-THINC 方案的高阶气体动力学通量求解器，用于可压缩流动

IF 2.5 3区工程技术 SCI

Computers & Fluids Pub Date : 2024-11-19 DOI: 10.1016/j.compfluid.2024.106492

Lan Jiang , Jie Wu , Liming Yang , Qiushuo Qin

{"title":"High-order gas kinetic flux solver with TENO-THINC scheme for compressible flows","authors":"Lan Jiang , Jie Wu , Liming Yang , Qiushuo Qin","doi":"10.1016/j.compfluid.2024.106492","DOIUrl":"10.1016/j.compfluid.2024.106492","url":null,"abstract":"<div><div>Although gas kinetic schemes (GKS) have been widely used as a potent tool for simulating compressible flows, they exhibit numerous drawbacks. Since most GKS are constructed based on the Maxwellian distribution function or its equivalent, the theoretical derivation and flux expression are often extremely complicated, which may result in lower calculation efficiency compared to traditional methods in computational fluid dynamics. In this paper, a circular function-based gas kinetic flux solver (C-GKFS) combined with a hybrid targeted essentially non-oscillatory-tangent of hyperbola for INterface capturing (TENO-THINC) scheme is presented for simulating two-dimensional compressible flows. The C-GKFS, which simplifies the Maxwellian distribution function into a circular function, significantly enhances computing efficiency. The TENO-THINC scheme, which combines the standard TENO scheme for smooth regions with the THINC scheme for non-smooth discontinuities, preserves low dissipation for smooth flow while effectively resolves the profile of jump for shock and contact waves. As a result, a simple high-order C-GKFS is obtained, which reduces complexity to facilitate practical engineering applications. Some benchmark problems are simulated, and good agreement can be obtained compared with reference data, which demonstrates that the TENO-THINC based C-GKFS achieves the desired accuracy and performs significantly better than the standard TENO scheme.</div></div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"287 ","pages":"Article 106492"},"PeriodicalIF":2.5,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142703519","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}

引用次数: 0

A new sharing function for the common-weights WENO reconstruction of the Euler equations 欧拉方程共权 WENO 重构的新共享函数

IF 2.5 3区工程技术 SCI

Computers & Fluids Pub Date : 2024-11-17 DOI: 10.1016/j.compfluid.2024.106479

Yiqiu Jin , Yiqing Shen , Guowei Yang , Guannan Zheng

引用次数: 0