International Journal for Numerical Methods in Fluids最新文献_第2页

Numerical Investigation and Machine Learning Predictions for Enhanced Thermal Management in Pulsating Heat Pipes: Modeling Turbulent Flow and Heat Transfer Characteristics in Nuclear Applications

IF 1.7 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-11-22 DOI: 10.1002/fld.5358

Erfan Khosravian

{"title":"Numerical Investigation and Machine Learning Predictions for Enhanced Thermal Management in Pulsating Heat Pipes: Modeling Turbulent Flow and Heat Transfer Characteristics in Nuclear Applications","authors":"Erfan Khosravian","doi":"10.1002/fld.5358","DOIUrl":"https://doi.org/10.1002/fld.5358","url":null,"abstract":"<div>\u0000 \u0000 <p>This paper presents a comprehensive numerical investigation of the performance of pulsating heat pipes (PHPs) within nuclear reactor cooling systems. A volume of fluid (VOF) method was used to simulate the complex multiphase flow, providing detailed insights into fluid distribution, phase interactions, and temperature variations under different operating conditions. The simulations revealed distinct phase separation and convective flow patterns that enhance heat transfer efficiency, which is critical for optimizing thermal management in nuclear reactors. Additionally, artificial neural network (ANN) models were employed to predict volume fractions and wall temperatures, achieving high accuracy with <i>R</i><sup>2</sup> values of 0.99 and 0.98, respectively, and low mean absolute errors (MAE). The ANN models also reduced computational time by 90% compared to traditional numerical simulations. These findings highlight the potential of PHPs to improve heat transfer in nuclear systems and demonstrate the practicality of ANN models for real-time thermal optimization. The research contributes to enhancing the safety and efficiency of nuclear reactor cooling systems, with broader implications for thermal management across various engineering applications.</p>\u0000 </div>","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":"97 4","pages":"446-461"},"PeriodicalIF":1.7,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143536061","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}

引用次数: 0

A Multi-Fidelity Model for Wave Energy Converters

IF 1.7 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-11-21 DOI: 10.1002/fld.5354

Beatrice Battisti, Giovanni Bracco, Michel Bergmann

{"title":"A Multi-Fidelity Model for Wave Energy Converters","authors":"Beatrice Battisti, Giovanni Bracco, Michel Bergmann","doi":"10.1002/fld.5354","DOIUrl":"https://doi.org/10.1002/fld.5354","url":null,"abstract":"<p>The objective of this study is to develop a three-dimensional numerical model for a floating point absorber wave energy converter in the presence of sea waves, considering its interaction with a bi-fluid flow (comprising air and water). The primary aim is to create an efficient computational tool that achieves two key objectives: firstly, reducing the computational time typically associated with high-fidelity Computational Fluid Dynamics (CFD) models, and secondly, curing the lack of accuracy of low-fidelity asymptotic or projection-based reduced-order models in regions subjected to viscous and highly nonlinear effects. To address these objectives, we propose a multi-fidelity model based on domain decomposition. This approach combines a high-fidelity CFD solver, which accurately captures the behavior in viscous and nonlinear regions, with a Reduced Order Model (ROM) based on Proper Orthogonal Decomposition (POD), tailored for weakly nonlinear regions. By integrating these components spatially, we simulate the dynamics of the floating body within a unified framework. This methodology ensures precise predictions of the body's motion for both in-sample (reproduction) and out-of-sample (prediction) configurations.</p>","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":"97 4","pages":"427-445"},"PeriodicalIF":1.7,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/fld.5354","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143536130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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

Novel Finite-Volume Complete Flux Approximation Schemes for the Incompressible Navier–Stokes Equations

IF 1.7 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-11-21 DOI: 10.1002/fld.5353

Chitranjan Pandey, J. H. M. ten Thije Boonkkamp, B. V. Rathish Kumar

{"title":"Novel Finite-Volume Complete Flux Approximation Schemes for the Incompressible Navier–Stokes Equations","authors":"Chitranjan Pandey, J. H. M. ten Thije Boonkkamp, B. V. Rathish Kumar","doi":"10.1002/fld.5353","DOIUrl":"https://doi.org/10.1002/fld.5353","url":null,"abstract":"<div>\u0000 \u0000 <p>We construct novel flux approximation schemes for the semidiscretized incompressible Navier–Stokes equations by finite-volume method on a staggered mesh. The calculation of the cell-face fluxes has been done by solving appropriate local <i>non-linear</i> boundary value problems (BVP). Consequently, the cell-face fluxes are represented as the sum of a homogeneous and an inhomogeneous flux; the homogeneous part represents the contribution of convection and viscous-friction, while the inhomogeneous part represents the contribution of the source terms. We derive three flux approximation schemes to include the impact of the source terms on the numerical fluxes. The first one is based on a homogeneous 1-D local BVP without source. The second scheme is based on an inhomogeneous 1-D local BVP considering only the pressure gradient term in the source. Finally, a complete flux scheme is derived which is based on an inhomogeneous 2-D local BVP. It takes into account both the gradient of the cross-flux and the pressure gradient in the source term. The numerical validation of the schemes is done for the benchmark lid-driven cavity flow for considerably high <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mtext>Reynolds</mtext>\u0000 </mrow>\u0000 <annotation>$$ mathrm{Reynolds} $$</annotation>\u0000 </semantics></math> numbers along with a numerical convergence test for the exact solution of the Taylor–Green vortex problem.</p>\u0000 </div>","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":"97 3","pages":"409-425"},"PeriodicalIF":1.7,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143117720","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}

引用次数: 0

A Diffuse Interface Model for Cavitation, Taking Into Account Capillary Forces

IF 1.7 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-11-20 DOI: 10.1002/fld.5350

Takfarines Ait-Ali, Sofiane Khelladi, Farid Bakir, Noureddine Hannoun, Xesús Nogueira, Luis Ramírez

{"title":"A Diffuse Interface Model for Cavitation, Taking Into Account Capillary Forces","authors":"Takfarines Ait-Ali, Sofiane Khelladi, Farid Bakir, Noureddine Hannoun, Xesús Nogueira, Luis Ramírez","doi":"10.1002/fld.5350","DOIUrl":"https://doi.org/10.1002/fld.5350","url":null,"abstract":"<div>\u0000 \u0000 <p>We consider the moving least squares method to solve compressible two-phase water-water vapor flow with surface tension. A diffuse interface model based on the Navier–Stokes and Korteweg equations is coupled with a suitable system of state equations that allows for a more realistic estimation of the pressure jump across the liquid–vapor interface as a function of temperature. We propose a simple formulation for computing the capillarity coefficient <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>λ</mi>\u0000 </mrow>\u0000 <annotation>$$ lambda $$</annotation>\u0000 </semantics></math> based on the surface tension and the thickness of the diffuse interface. A convergence analysis using pressure jump in the test case of static bubble is conducted to verify our solver. We present several numerical test cases that illustrate the ability of our model to reproduce qualitatively and quantitatively the effects of surface tension on cavitation bubbles in general situations.</p>\u0000 </div>","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":"97 3","pages":"395-408"},"PeriodicalIF":1.7,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143117049","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}

引用次数: 0

A Time-Space Dual Adaptive Uncoupled Method for Supersonic Combustion

IF 1.7 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-11-18 DOI: 10.1002/fld.5351

Junjie Wu, Xun Xu, Xuke Zhang, Bin Zhang

{"title":"A Time-Space Dual Adaptive Uncoupled Method for Supersonic Combustion","authors":"Junjie Wu, Xun Xu, Xuke Zhang, Bin Zhang","doi":"10.1002/fld.5351","DOIUrl":"https://doi.org/10.1002/fld.5351","url":null,"abstract":"<div>\u0000 \u0000 <p>High computational complexity due to rapidly increasing numerical stiffness is a difficult problem for simulating a supersonic reactive flow by using the uncoupled method. On the basis of our previous work, this paper proposes a dual adaptive method to ensure high calculation efficiency and good robustness in simulating stiff cases. The principle of this method is to realize adaptive coordination for the advection and reaction time steps in accordance with the non-uniform feature of stiffness in the space and time dimensions. The proposed method can advance by a small time step in strong stiffness while with a large one in weak stiffness through the “prediction-correction-recovery” strategy. Some classical problems are chosen to verify the performance of the proposed method. The proposed method improved the computation efficiency by at least <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>30</mn>\u0000 <mo>%</mo>\u0000 </mrow>\u0000 <annotation>$$ 30% $$</annotation>\u0000 </semantics></math> comparing with the previous method [1] and widened the error tolerance of the initial time step.</p>\u0000 </div>","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":"97 3","pages":"378-394"},"PeriodicalIF":1.7,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143116441","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}

引用次数: 0

Fully Coupled, Higher-Order, Block-Structured Mesh Generation in Fluid–Structure Interaction

IF 1.7 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-11-14 DOI: 10.1002/fld.5355

Teresa Schwentner, Thomas-Peter Fries

引用次数: 0

Sim-Net: Simulation Net for Solving Seepage Equation Under Unsteady Boundary

IF 1.7 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-11-13 DOI: 10.1002/fld.5356

Daolun Li, Enyuan Chen, Yantao Xu, Wenshu Zha, Luhang Shen, Dongsheng Chen

{"title":"Sim-Net: Simulation Net for Solving Seepage Equation Under Unsteady Boundary","authors":"Daolun Li, Enyuan Chen, Yantao Xu, Wenshu Zha, Luhang Shen, Dongsheng Chen","doi":"10.1002/fld.5356","DOIUrl":"https://doi.org/10.1002/fld.5356","url":null,"abstract":"<div>\u0000 \u0000 <p>The seepage equation plays a crucial role in fields such as groundwater management, petroleum engineering, and civil engineering. Currently, physical-informed neural networks (PINNs) have become an effective tool for solving seepage equations. However, practical applications often involve variable flow rates, which pose significant challenges for using neural networks to find solutions. Inspired by Deep Operator Network (DeepONet), this paper proposes a new model named Simulation Net (Sim-net) to deal with unsteady sources or sinks problems. Sim-net is designed to simulate and solve seepage equations without the need for retraining. This model integrates potential spatial and temporal features based on spatial pressure distribution and well bottom–hole pressure, respectively, which serve as additional signposts to guide neural networks in approximating seepage equations. Sim-net exhibits transfer learning capabilities, enabling it to handle variable flow rate problems without retraining for new flow conditions. Numerical experiments demonstrate that the trained model can directly solve seepage equations without the need for retraining, indicating its superior applicability compared to existing PINNs-based methods. Additionally, in comparison to the DeepONet, Sim-net achieves higher accuracy.</p>\u0000 </div>","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":"97 3","pages":"345-358"},"PeriodicalIF":1.7,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143114554","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}

引用次数: 0

Numerical Prediction of Cavitation Erosion Risk Based on a New Erosion Indicator

IF 1.7 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-11-09 DOI: 10.1002/fld.5347

Xiaoyu Wang, Junqi Ma, Tian Wang, Qiang Sun

引用次数: 0

Comparison of Contact Angle Models in Two-Phase Flow Simulations Using a Conservative Phase Field Equation

IF 1.7 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-11-04 DOI: 10.1002/fld.5352

Mingguang Shen, Ben Q. Li

{"title":"Comparison of Contact Angle Models in Two-Phase Flow Simulations Using a Conservative Phase Field Equation","authors":"Mingguang Shen, Ben Q. Li","doi":"10.1002/fld.5352","DOIUrl":"https://doi.org/10.1002/fld.5352","url":null,"abstract":"<p>In phase field methods based on a second-order Allen-Cahn (AC) equation, contact angles are prescribed mostly via a geometric formulation. However, it is of great interest to utilize the surface-energy formulation, which is often employed in the Cahn-Hilliard (CH) phase field method, in the AC phase field method. This article thus put forward a surface-energy formulation of contact angles. The model was compared with the geometric one in a number of impact problems, including both normal and oblique impacts. The governing equations were discretized using a finite difference method on a half-staggered grid. The Navier–Stokes equation was tackled using an explicit projection method. The major findings are as follows. First, the geometric model can maintain a fixed contact angle throughout contact line motion, while the surface-energy one predicts a changeable contact angle, with a fluctuation of about 5°. In the oblique drop impact, contact angle hysteresis was captured even if a static contact angle was applied in the surface-energy formulation.</p>","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":"97 3","pages":"315-328"},"PeriodicalIF":1.7,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/fld.5352","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143111999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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

A Hybrid Approach of Buongiorno's Law and Darcy–Forchheimer Theory Using Artificial Neural Networks: Modeling Convective Transport in Al2O3-EO Mono-Nanofluid Around a Riga Wedge in Porous Medium

IF 1.7 4区工程技术

International Journal for Numerical Methods in Fluids Pub Date : 2024-11-04 DOI: 10.1002/fld.5348

Anum Shafiq, Andaç Batur Çolak, Tabassum Naz Sindhu

{"title":"A Hybrid Approach of Buongiorno's Law and Darcy–Forchheimer Theory Using Artificial Neural Networks: Modeling Convective Transport in Al2O3-EO Mono-Nanofluid Around a Riga Wedge in Porous Medium","authors":"Anum Shafiq, Andaç Batur Çolak, Tabassum Naz Sindhu","doi":"10.1002/fld.5348","DOIUrl":"https://doi.org/10.1002/fld.5348","url":null,"abstract":"<div>\u0000 \u0000 <p>The inspiration for this study originates from a recognized research gap within the broader collection of studies on nanofluids, with a specific focus on their interactions with different surfaces and boundary conditions (BCs). The primary purpose of this research is to use an artificial neural network to examine the combination of Alumina-Engine oil-based nanofluid flow subject to electro-magnetohydrodynamic effects, within a porous medium, and over a stretching surface with an impermeable structure under convective BCs. The flow model incorporates Thermophoresis and Brownian motion directly from Buongiorno's model. Accounting for the porous medium's effect, the model integrates the Forchheimer number (depicting local inertia) and the porosity factor developed in response to the presence of the porous medium. The conversion of governing equations into non-linear ordinary differential systems is achieved by implementing transformations. A highly non-linear ordinary differential system's final system is solved using a numerical scheme (Runge–Kutta fourth-order). Findings indicate that the porosity factor positively impacts the skin friction and the momentum boundary layer. The influence suggests an increment in the frictional force and a decline in the velocity profile. The volume fraction, Prandtl number, and magnetic number significantly impact the flow profiles. The skin friction data is tabulated with some physical justifications.</p>\u0000 </div>","PeriodicalId":50348,"journal":{"name":"International Journal for Numerical Methods in Fluids","volume":"97 3","pages":"299-314"},"PeriodicalIF":1.7,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143112017","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}

引用次数: 0