Computers & Fluids最新文献_第10页

Qubit lattice algorithm simulations of Maxwell’s equations for scattering from anisotropic dielectric objects 各向异性介质散射麦克斯韦方程组的量子比特点阵算法模拟

IF 2.8 3区工程技术

Computers & Fluids Pub Date : 2023-08-22 DOI: 10.1016/j.compfluid.2023.106039

George Vahala , Min Soe , Linda Vahala , Abhay K. Ram , Efstratios Koukoutsis , Kyriakos Hizanidis

{"title":"Qubit lattice algorithm simulations of Maxwell’s equations for scattering from anisotropic dielectric objects","authors":"George Vahala , Min Soe , Linda Vahala , Abhay K. Ram , Efstratios Koukoutsis , Kyriakos Hizanidis","doi":"10.1016/j.compfluid.2023.106039","DOIUrl":"https://doi.org/10.1016/j.compfluid.2023.106039","url":null,"abstract":"<div>A Dyson map explicitly determines the appropriate basis of electromagnetic fields which yields a unitary representation of the Maxwell equations in an inhomogeneous medium. A qubit lattice algorithm (QLA) is then developed perturbatively to solve this representation of Maxwell equations. A QLA consists of an interleaved unitary sequence of collision operators (that entangle on lattice-site qubits) and streaming operators (that move this entanglement throughout the lattice). External potential operators are introduced to handle gradients in the refractive indices, and these operators are typically non-unitary but sparse matrices. By also interleaving the external potential operators with the unitary collide-stream operators, one achieves a QLA which conserves energy to high accuracy. Some two dimensional simulations results are presented for the scattering of a one-dimensional (1D) pulse off a localized anisotropic dielectric object.</div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"266 ","pages":"Article 106039"},"PeriodicalIF":2.8,"publicationDate":"2023-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92039631","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: 4

General fourth-order Chapman–Enskog expansion of lattice Boltzmann schemes 点阵玻尔兹曼格式的一般四阶Chapman-Enskog展开

IF 2.8 3区工程技术

Computers & Fluids Pub Date : 2023-08-22 DOI: 10.1016/j.compfluid.2023.106036

François Dubois , Bruce M. Boghosian , Pierre Lallemand

引用次数: 0

Numerical simulation of aortic coarctations of different grades of severity: Flow features and importance of outlet boundary conditions 不同严重程度主动脉缩窄的数值模拟:流动特征和出口边界条件的重要性

IF 2.8 3区工程技术

Computers & Fluids Pub Date : 2023-08-22 DOI: 10.1016/j.compfluid.2023.106043

A. Mariotti , M.N. Antonuccio , M. Morello , M.V. Salvetti , S. Celi

{"title":"Numerical simulation of aortic coarctations of different grades of severity: Flow features and importance of outlet boundary conditions","authors":"A. Mariotti , M.N. Antonuccio , M. Morello , M.V. Salvetti , S. Celi","doi":"10.1016/j.compfluid.2023.106043","DOIUrl":"https://doi.org/10.1016/j.compfluid.2023.106043","url":null,"abstract":"<div>Numerical simulations of the blood flow inside a patient-specific thoracic aorta in presence of coarctation are considered. Different grades of severity of the coarctation are obtained by constructing parametric geometries in which the coarctation section is circular with varying diameter values. The impact of a fine-tuning of the Windkessel model resistances, at each outlet, is also investigated. A stochastic approach based on the generalized Polynomial Chaos (gPC) is used to carry out a systematic analysis. It allows obtaining continuous response surfaces of the quantities of interest in the parameter space from a limited number of simulations. Two parameters are selected: the vessel diameter, <math><mi>D</mi></math>, at the coarctation plane and a non-dimensional parameter, <math><mi>α</mi></math>, through which it is possible to calibrate the resistance offered by organs and vessels downstream the thoracic aorta. The value of the coarctation diameter has the strongest impact on all the flow features, i.e., flow rate, pressure, velocity, and wall shear stresses. It is also shown that, as the value of <math><mi>D</mi></math> increases, the dependence on <math><mi>α</mi></math> decreases. This means that the more the geometry of the thoracic aorta approaches a healthy shape, the less significant it is to perform a fine-tuning of the Windkessel model resistances to match the patient-specific pressure waveform, whereas it should be done in cases of severe coarctations.</div>","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"266 ","pages":"Article 106043"},"PeriodicalIF":2.8,"publicationDate":"2023-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0045793023002682/pdfft?md5=3a9dd038a3d2e464dcf20ea1599ca9ae&pid=1-s2.0-S0045793023002682-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92039638","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

Sill Role Effect on the Flow Characteristics (Experimental and Regression Model Analytical) still Role对流动特性的影响(实验与回归模型分析)

IF 2.8 3区工程技术

Computers & Fluids Pub Date : 2023-08-21 DOI: 10.3390/fluids8080235

Hamidreza Abbaszadeh, R. Norouzi, Veli Sume, Alban Kuriqi, R. Daneshfaraz, J. Abraham

引用次数: 0

Effect of Serpentine Flow Field Channel Dimensions and Electrode Intrusion on Flow Hydrodynamics in an All-Iron Redox Flow Battery 蛇形流场、通道尺寸和电极侵入对全铁氧化还原液流电池流体力学的影响

IF 2.8 3区工程技术

Computers & Fluids Pub Date : 2023-08-21 DOI: 10.3390/fluids8080237

Rakesh Basavegowda Krishnappa, S. G. Subramanya, Abhijit R Deshpande, B. Chakravarthi

{"title":"Effect of Serpentine Flow Field Channel Dimensions and Electrode Intrusion on Flow Hydrodynamics in an All-Iron Redox Flow Battery","authors":"Rakesh Basavegowda Krishnappa, S. G. Subramanya, Abhijit R Deshpande, B. Chakravarthi","doi":"10.3390/fluids8080237","DOIUrl":"https://doi.org/10.3390/fluids8080237","url":null,"abstract":"This paper presents a study on flow hydrodynamics for single-channel serpentine flow field (SCSFF) and cross-split serpentine flow field configurations (CSSFF) for different geometric dimensions of channel and rib width ratios with electrode intrusion over varying compression ratios (CRs) in an all-iron redox flow battery. Pressure drops (Δp) measured experimentally across a cell active area of 131 cm2 for different electrolyte flow rates were numerically validated. A computational fluid dynamics study was conducted for detailed flow analyses, velocity magnitude contours, flow distribution, and uniformity index for the intrusion effect of a graphite felt electrode bearing a thickness of 6 mm with a channel compressed to varying percentages of 50%, 60%, and 70%. Experimental pressure drops (Δp) over the numerical value resulted in the maximum error approximated to 4%, showing good agreement. It was also reported that the modified version of the cross-split serpentine flow field, model D, had the lowest pressure drop, Δp, of 2223.4 pa, with a maximum uniformity index at the electrode midplane of 0.827 for CR 50%, across the active cell area. The pressure drop (Δp) was predominantly higher for increased compression ratios, wherein intrusion phenomena led to changes in electrochemical activity; it was found that the velocity distribution was quite uniform for a volumetric uniformity index greater than 80% in the felt.","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"1 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2023-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83124139","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 Parametric Design Study of Natural-Convection-Cooled Heat Sinks 自然对流冷却散热器的参数化设计研究

IF 2.8 3区工程技术

Computers & Fluids Pub Date : 2023-08-21 DOI: 10.3390/fluids8080234

Oisín McCay, R. Nimmagadda, Syed Mughees Ali, T. Persoons

{"title":"A Parametric Design Study of Natural-Convection-Cooled Heat Sinks","authors":"Oisín McCay, R. Nimmagadda, Syed Mughees Ali, T. Persoons","doi":"10.3390/fluids8080234","DOIUrl":"https://doi.org/10.3390/fluids8080234","url":null,"abstract":"Effective natural-convection-cooled heat sinks are vital to the future of electronics cooling due to their low energy demand in the absence of an external pumping agency in comparison to other cooling methods. The present numerical study was carried out with ANSYS Fluent and aimed at identifying a more-effective fin design for enhancing heat transfer in natural convection applications for a fixed base-plate size of 100 mm × 100 mm under an applied heat flux of 4000 W/m2. The Rayleigh number used in the present study lied within the range of 2.6 × 106 to 4.5 × 106. Initially, a baseline case with rectangular fins was considered in the present study, and it was optimized with respect to fin spacing. This optimized baseline case was then validated against the semi-empirical correlation from the scientific literature. Upon good agreement, the validated model was used for comparative analysis of different heat sink configurations with rectangular, trapezoidal, curved, and angled fins by constraining the surface area of the heat transfer. The optimized fin spacing obtained for the baseline case was also used for the other heat sink configurations, and then, the fin designs were further optimized for better performance. However, for the angled fin case, the optimized configuration found in the scientific literature was adopted in the present study. The proposed novel curved fin design with a shroud showed a 4.1% decrease in the system’s thermal resistance with an increase in the heat transfer coefficient of 4.4% when compared to the optimized baseline fin case. The obtained results were further non-dimensionalized with the proposed scaling in terms of the baseline case for the two novel heat sink cases (trapezoidal, curved).","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"21 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2023-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81049495","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

Hybrid Computation of the Aerodynamic Noise Radiated by the Wake of a Subsonic Cylinder 亚音速圆柱尾迹辐射气动噪声的混合计算

IF 2.8 3区工程技术

Computers & Fluids Pub Date : 2023-08-21 DOI: 10.3390/fluids8080236

Benet Eiximeno, Carlos Tur-Mongé, O. Lehmkuhl, I. Rodríguez

{"title":"Hybrid Computation of the Aerodynamic Noise Radiated by the Wake of a Subsonic Cylinder","authors":"Benet Eiximeno, Carlos Tur-Mongé, O. Lehmkuhl, I. Rodríguez","doi":"10.3390/fluids8080236","DOIUrl":"https://doi.org/10.3390/fluids8080236","url":null,"abstract":"The noise radiated by the flow around a cylinder in the subcritical regime at ReD=1×104 and at a subsonic Mach number of M=0.5 is here studied. The aerodynamic sound radiated by a cylinder has been studied with a wide range of Reynolds numbers, but there are no studies about how the Mach number affects the acoustic field in the subsonic regime. The flow field is resolved by means of large-eddy simulations of the compressible Navier–Stokes equations. For the study of the noise propagation, formulation 1C of the Ffowcs Williams–Hawkings analogy is used. The fluid flow results show good agreement when comparing the surface pressure coefficient, the recirculation length, the vortex shedding frequency and the force coefficients against other studies performed under similar conditions. The dynamic mode decomposition of the pressure fluctuations is used to relate them with the far-field noise. It is shown that, in contrast to what happens for low Mach numbers, quadrupoles have a significant impact mainly in the observers located in the streamwise direction. This effect leads to a global monopole directivity pattern as the shear fluctuations compensate for the lower value of the aeolian tone away from the cross-stream direction.","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"42 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2023-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82456484","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 preconditioning for the spectral solution of incompressible variable-density flows 不可压缩变密度流谱解的一个先决条件

IF 2.8 3区工程技术

Computers & Fluids Pub Date : 2023-08-19 DOI: 10.1016/j.compfluid.2023.106024

L. Reynier , B. Di Pierro , F. Alizard , A. Cadiou , L. Le Penven , M. Buffat

引用次数: 0

Korteweg–De Vries–Burger Equation with Jeffreys’ Wind–Wave Interaction: Blow-Up and Breaking of Soliton-like Solutions in Finite Time Korteweg-De Vries-Burger方程与Jeffreys的风波相互作用:有限时间内类孤子解的爆破与破裂

IF 2.8 3区工程技术

Computers & Fluids Pub Date : 2023-08-19 DOI: 10.3390/fluids8080231

M. Manna, A. Latifi

{"title":"Korteweg–De Vries–Burger Equation with Jeffreys’ Wind–Wave Interaction: Blow-Up and Breaking of Soliton-like Solutions in Finite Time","authors":"M. Manna, A. Latifi","doi":"10.3390/fluids8080231","DOIUrl":"https://doi.org/10.3390/fluids8080231","url":null,"abstract":"In this study, the evolution of surface water solitary waves under the action of Jeffreys’ wind–wave amplification mechanism in shallow water is analytically investigated. The analytic approach is essential for numerical investigations due to the scale of energy dissipation near coasts. Although many works have been conducted based on the Jeffreys’ approach, only some studies have been carried out on finite depth. We show that nonlinearity, dispersion, and anti-dissipation are the dominating phenomena, obeying an anti-diffusive and fully nonlinear Serre–Green–Naghdi (SGN) equation. Applying an appropriate perturbation method, the current research yields a Korteweg–de Vries–Burger-type equation (KdV-B), combining weak nonlinearity, dispersion, and anti-dissipation. This derivation is novel. We show that the continuous transfer of energy from wind to water results in the growth over time of the KdV-B soliton’s amplitude, velocity, acceleration, and energy, while its effective wavelength decreases. This phenomenon differs from the classical results of Jeffreys’ approach and is due to finite depth. In this study, it is shown that expansion and breaking occur in finite time. These times are calculated and expressed with respect to soliton- and wind-appropriateparameters and values. The obtained values are measurable in experimental facilities. A detailed analysis of the breaking time is conducted with regard to various criteria. By comparing these times to the experimental results, the validity of these criteria are examined.","PeriodicalId":287,"journal":{"name":"Computers & Fluids","volume":"28 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2023-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81210796","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 Stabilized Finite Element Framework for Anisotropic Adaptive Topology Optimization of Incompressible Fluid Flows 不可压缩流体流动各向异性自适应拓扑优化的稳定有限元框架

IF 2.8 3区工程技术

Computers & Fluids Pub Date : 2023-08-19 DOI: 10.3390/fluids8080232

Wassim Abdel Nour, Joseph Jabbour, D. Serret, P. Meliga, E. Hachem

引用次数: 0