Application Of Fluid Dynamics Research Articles

BIM and Computational Fluid Dynamics Analysis for Thermal Management Improvement in Data Centres

One of the most energy-intensive facilities requiring a comprehensive and well-optimised cooling system is the data centre. Air containment across the data centre is a key thermal management and energy-saving strategy that enhances the performance of data centres. The majority of modern energy-efficient data centres use some type of air containment. The primary advantage of aisle separation and containment is the decrease in the air temperature at the server inlet by reducing the mixing of hot air with cold air. In order to ascertain the volume of literature relating to corridor insulation, we conducted a literature review. Currently, there have been numerous articles regarding the application of computational fluid dynamics (CFD) analysis, however, publications delineating the integration of building information modelling (BIM) principles for corridor separation are still limited. Research specifically targeting data centre corridor insulation is somewhat limited. As a result of this analysis, the most common methods used to isolate hot or cold aisles within a data centre were identified. To determine the most effective type of corridor insulation, the BIM family was created in Autodesk Revit. The model includes 15 telecom cabinets containing information technology (IT) equipment, eight inter-row air conditioners, and one UPS. The model was used for the CFD analysis of the air temperature in different zones of the room. Visualisation of the results using gradient temperature distributions at different levels provides a complete picture of the microclimate formation in the room and allowed the advantage of the hot aisle isolation scheme to be demonstrated.

Special Issue on Industrial Applications of Computational Fluid Dynamics

The CFD (Computational Fluid Dynamics) method can be used in various areas that concern almost every field of technology, including water bodies, air spaces, as well as technical devices and machines [...]

Application of computational fluid dynamics in design of viscous dampers - CFD modeling and full-scale dynamic testing

Application of computational fluid dynamics in design of viscous dampers - CFD modeling and full-scale dynamic testing

Best Practices for Computational Fluid Dynamic Applications in Water Infrastructure

Best Practices for Computational Fluid Dynamic Applications in Water Infrastructure

Multi-Peak and Propagation Behavior of M-Shape Solitons in (2 + 1)-Dimensional Integrable Schwarz-Korteweg-de Vries Problem

This paper examines the propagation of M-shape solitons and their interactions with kink waves to the (2 + 1)-dimensional integrable Schwarz-Korteweg-de Vries (ISKdV) problem by applying the symbolic computation with ansatz functions technique and logarithmic transformation. The governing model usually appears in the nonlinear shallow water waves and fluid mechanics. We discuss various nonlinear waves like multiwave solutions (MSs), homoclinic breather (HB), M-shape solitons, single exponential form (one-kink), and double exponential form (two-kink). These waves have lot of applications in fluid dynamics, nonlinear optics, chemical reaction networks, biological systems, climate science, and material science. We also study interaction among M-shape solitons with kink wave. At the end, we discuss the stability characteristics of all solutions.

Enhancing the Reliability Assessment System for Crucial Powertrain Components through Design, Simulation, and Experiment

Article Enhancing the Reliability Assessment System for Crucial Powertrain Components through Design, Simulation, and Experiment Xiaochun Zeng 1,2,3, Gongcheng Wang 1,* , Ying Liu 2,3, Jing Liu 1,2,3, Yinglian Feng 2,3,4, Xiuyong Shi 5,6, Diming Lou 5,6, Lei Zhang 4, Tao Wei 1, and Zhong Li 1 1 Jiangling Motors Co. Ltd., Nanchang 330001, China 2 Jiangxi Province Women Science and Technology Workers Association, Nanchang 330036, China 3 Jiangxi Mechanical Engineering Society, Nanchang 330002, China 4 Magna PT Powertrain (Jiangxi), Nanchang 330200, China 5 Nanchang Automotive Institute of Intelligence & New Energy, Nanchang 330052, China 6 Tongji University, Shanghai 200092, China * Correspondence: gwang7@jmc.com.cn Received: 5 September 2023 Accepted: 19 September 2023 Published: 20 September 2023 Abstract: This article conducted innovative research on heat balance, cooling and structural strength by using Computer Aided Engineering (CAE), design, and experiment. These multifaceted approaches rely on the meticulous application of dynamic analysis, combustion analysis, fluid dynamics, and finite element analysis. This research has devised a fatigue-oxidation-creep multi-fatigue life prediction technique for thermal engines, coupled with an innovative water jacket optimization method. By addressing the design challenges arising from the demanding requirements of high explosion pressure, formidable power, and significant torque in power systems, this study has made significant strides in advancing the field. And this method was used to establish the development capability of powertrain electric drive components. To enhance reliability and prediction accuracy, a simulation and test calibration method was devised for Crucial Powertrain Components. This article establishes a robust foundation by providing comprehensive data support for reliability target decomposition, facilitating the efficient derivation of component reliability metrics. Additionally, it explores potential customer scenario failures and investigates the underlying mechanisms of powertrain malfunctions. By establishing a correlation matrix between failure modes, mechanisms, and reliability experiments, the coverage of powertrain failure mode verification experiments was significantly increased by over 95%. Ultimately, this article contributes to the formation of a comprehensive technical system for evaluating the reliability of crucial powertrain components, integrating design, simulation, and experiment.

Study on hydroturbine power trend prediction based on machine learning

The application of computational fluid dynamics combined with 3D modeling of the hydraulic model was discussed in this paper. Through the complex calculation of the internal low field, dynamic simulation was used to predict the characteristics of water energy index. Based on the collection of a large number of different types of turbine operation data in different working conditions, the improved multi-layer neural network power prediction model based on the adaptive inverse normalization strategy and the improved grey wolf algorithm were used to optimize the least squares support vector machine power prediction model. Rlue activation function was used in the improved multi-layer neural network model uses to improve the computation speed and prevent gradient disappearance. Combined with L2 regularization to prevent data overfitting, Adam gradient optimizer was applied to achieve fast convergence of network output. The simulation results shown that the method can realize the high precision prediction of turbine output power.

Application of Patient-Specific Computational Fluid Dynamics in Anomalous Aortic Origin of Coronary Artery: A Systematic Review.

Anomalous aortic origin of a coronary artery (AAOCA) is a rare congenital heart condition with fixed and dynamic stenotic elements, potentially causing ischemia. Invasive coronary angiography under stress is the established method for assessing hemodynamics in AAOCA, yet it is costly, technically intricate, and uncomfortable. Computational fluid dynamics (CFD) simulations offer a noninvasive alternative for patient-specific hemodynamic analysis in AAOCA. This systematic review examines the role of CFD simulations in AAOCA, encompassing patient-specific modeling, noninvasive imaging-based boundary conditions, and flow characteristics. Screening articles using AAOCA and CFD-related terms prior to February 2023 yielded 19 publications, covering 370 patients. Over the past four years, 12 (63%) publications (259 patients) employed dedicated CFD models, whereas 7 (37%) publications (111 patients) used general-purpose CFD models. Dedicated CFD models were validated for fixed stenosis but lacked dynamic component representation. General-purpose CFD models exhibited variability and limitations, with fluid-solid interaction models showing promise. Interest in CFD modeling of AAOCA has surged recently, mainly utilizing dedicated models. However, these models inadequately replicate hemodynamics, necessitating novel CFD approaches to accurately simulate pathophysiological changes in AAOCA under stress conditions.

A Fourier-based methodology without numerical diffusion for conducting dye simulations and particle residence time calculations

Dye experimentation is a widely used method in experimental fluid mechanics for flow analysis or for the study of the transport of particles within a fluid. This technique is particularly useful in biomedical diagnostic applications ranging from hemodynamic analysis of cardiovascular systems to ocular circulation. However, simulating dyes governed by convection-diffusion partial differential equations (PDEs) can also be a useful post-processing analysis approach for computational fluid dynamics (CFD) applications. Such simulations can be used to identify the relative significance of different spatial subregions in particular time intervals of interest in an unsteady flow field. Additionally, dye evolution is closely related to non-discrete particle residence time (PRT) calculations that are governed by similar PDEs. This contribution introduces a pseudo-spectral method based on Fourier continuation (FC) for conducting dye simulations and non-discrete particle residence time calculations without numerical diffusion errors. Convergence and error analyses are performed with both manufactured and analytical solutions. The methodology is applied to three distinct physical/physiological cases: 1) flow over a two-dimensional (2D) cavity; 2) pulsatile flow in a simplified partially-grafted aortic dissection model; and 3) non-Newtonian blood flow in a Fontan graft. Although velocity data is provided in this work by numerical simulation, the proposed approach can also be applied to velocity data collected through experimental techniques such as from particle image velocimetry.

Application of computational fluid dynamics for simulation of stirred bioreactors in Ansys Fluent

Stirred bioreactors are widely used in the pharmaceutical industry to produce various active substances for the treatment of cancer, heart and vascular diseases, viral and bacterial infections. Despite the widespread use of bioreactors with a stirrer, the optimization of mixing conditions remains an urgent task. In bioreactors of this type, continuous mixing of cells in a medium with a high rotation speed should be carried out. The manuscript considers an example of the use of computational fluid dynamics to study and model the process of cultivation Escherichia coli bacterial cells in a batch bioreactor (NLF, 30 l.). Computational fluid dynamics was used to analyze the hydrodynamic conditions in a bioreactor with a double Rushton turbine stirrer. To describe the movement of flows and evaluate turbulence in a batch bioreactor, the multiphase Euler model and the k-𝜀 turbulence model, respectively, were used, the built-in Ansys Fluent software package. A geometric model was built with the original dimensions of the bioreactor with an NLF 30 stirrer. Based on the geometric model, a computational grid was created for the working volume of the bioreactor and the optimal parameters for constructing the computational grid were selected. As a result of modeling the hydrodynamic regime, the distribution profiles of the turbulence kinetic energy over the volume of the bioreactor were obtained and the velocities of cell movement were found at different speeds of rotation of the stirrer. The obtained results show the possibility and applicability of the Ansys Fluent software package for calculating the hydrodynamic situation in a bioreactor with a stirrer at different stirring rates and at different cell volume fractions.

Fractional generalized perturbed KdV equation with a power Law kernel: A computational study

In this study, we analyze the nonlinear generalized perturbed KdV equation using the Shehu transform and decomposition approach to obtain solutions. Multiple cases with appropriate initial conditions demonstrate the procedure’s effectiveness and validity, with excellent agreements noted. Simulations reveal three distinct solutions: one bright-soliton, two wave solutions, and dark-bright soliton solutions. Fractional order significantly impacts wave amplitudes and nonlinearity characteristics, affecting system excitations. These findings offer insights into complex behaviors, with potential applications in fluid dynamics, nonlinear optics, and plasma physics, guiding experimental design and system analysis.

A technical review of computational fluid dynamics (CFD) applications on wind design of tall buildings and structures: Past, present and future

Over the past two decades, an upsurge in using Computational Fluid Dynamics (CFD) for wind design on tall buildings has been observed. An extensive amount of work has been performed, where validation has been at the forefront of most of these studies. Challenges associated with CFD and different methodologies used in the analysis haven't been well articulated within the scope of tall building design. Also, there is a lack of critical best practice guidelines in using CFD for wind analysis of structures which can be readily adopted by practitioners and researchers alike. To this end, this paper presents a comprehensive technical review of the application of Computational Fluid Dynamics (CFD) on tall buildings and structures. A thorough discussion of CFD and its concerning design challenges specific to tall building design, such as turbulence modelling, inflow turbulence and domain & mesh configurations, are discussed in detail. Furthermore, a comprehensive literature of CFD studies on tall buildings is presented, covering all important topics from basic bluff body aerodynamics to complex Fluid-Structure Interaction (FSI) studies. Where applicable, the literature is critically evaluated (impartially) in this paper and compared with supportive arguments from the author's extensive experience. Finally, the manuscript concludes with potential upcoming numerical methods such as the Lattice-Boltzmann Method (LBM) and the use of Artificial Intelligence (AI) to design tall buildings.

IDEFIX: A versatile performance-portable Godunov code for astrophysical flows

Context. The exascale super-computers becoming available rely on hybrid energy-efficient architectures that involve an accelerator such as a graphics processing unit (GPU). Leveraging the computational power of these machines often means a significant rewrite of the numerical tools each time a new architecture becomes available. Aims. We present IDEFIX, a new code for astrophysical flows that relies on the KOKKOS meta-programming library to guarantee performance portability on a wide variety of architectures while keeping the code as simple as possible to the user. Methods. IDEFIX is based on a Godunov finite-volume method that solves the nonrelativistic hydrodynamical (HD) and magnetohy-drodynamical (MHD) equations on various grid geometries. IDEFIX includes a large choice of solvers and several additional modules (constrained transport, orbital advection, nonideal MHD), allowing users to address complex astrophysical problems. Results. IDEFIX has been successfully tested on Intel and AMD CPUs (up to 131 072 CPU cores on Irene-Rome at TGCC) as well as NVidia and AMD GPUs (up to 1024 GPUs on Adastra at CINES). IDEFIX achieves more than 108 cell s−1 in MHD on a single NVidia V100 GPU and 3 × 1011 cell s−1 on 256 Adastra nodes (1024 GPUs) with 95% parallelization efficiency (compared to single node). For the same problem, IDEFIX is up to six times more energy efficient on GPUs compared to Intel Cascade Lake CPUs. Conclusions. IDEFIX is now a mature exascale-ready open-source code that can be used on a large variety of astrophysical and fluid dynamics applications.

G. Rozza, G. Stabile, F. Ballarin: “Advanced Reduced Order Methods and Applications in Computational Fluid Dynamics”

G. Rozza, G. Stabile, F. Ballarin: “Advanced Reduced Order Methods and Applications in Computational Fluid Dynamics”

Hydrodynamic Simulation and Analysis Using Computational Fluid Dynamics: Electrochemical Reactors and Redox Flow Batteries

AbstractState‐of‐the‐art applications of computational fluid dynamics (CFD) in the analysis and optimization of electrochemical reactors and redox flow batteries are reviewed. Various factors are covered which affect the efficiency of electrochemical reactors and redox flow batteries created using CFD simulation approaches, including physical and chemical factors, such as pH, treatment time, temperature, and the conductivity of the solution, as well as design elements like inter‐electrode distance and electrode materials. Different hydrodynamic variables are discussed that impact the efficiency of these systems, such as pressure distribution, velocity, tracer mass fraction, geometry, flow‐based electrochemical energy storage, and residence time distribution. Although CFD methods are reliable, more straightforward, and cost‐effective, also the limitations of CFD and the challenges are considered that remain in its development and application in electrochemical engineering. The significant progress made in the use of CFD to study electrochemical reactors and redox flow batteries and the technology's potential to improve the efficiency and sustainability of these technologies are emphasized.

Modeling impedance boundary conditions and acoustic barriers using the immersed boundary method: The three-dimensional case.

One of the main challenges in time domain wave-based acoustics is the accurate simulation of both boundary conditions and barriers capable of reflecting and transmitting energy. Such scattering structures are generally of irregular geometry and characterised in terms of frequency-dependent reflectances and transittances. Conditions for numerical stability can be difficult to obtain in either case. Immersed boundary methods, which are heavily used in computational fluid dynamics applications, replace boundaries by discrete driving terms, avoiding volumetric meshing and staircasing approaches altogether. The main contribution of this article is a unified numerical treatment of both impedance boundary conditions and barriers capable of transmitting energy and suitable for use in the setting of wave-based acoustics. It is framed in terms of the immersed boundary method within a finite difference time domain scheme, using a dual set of matched discrete driving terms in both the conservation of mass and momentum equations that can be tuned against a desired reflectance or transmittance. Numerical results in three dimensions are presented, illustrating non-porous barriers and impedance boundary conditions, and highlight important features such as spurious leakage through an immersed boundary. A brief demonstration of conditions for numerical stability of the immersed boundary method in this context is provided in an appendix.

Pressure and flow transition over NACA airfoil with thrust optimized parabolic arcs

This paper presents an accurate prediction of surface drag, pressure coefficient and flow transition around a symmetric airfoil design through the implementation of finite element discretization. Skin friction coefficient has been analyzed at different Reynolds number and at various angles of attack for NACA0012 airfoil design. The transition from laminar to turbulent flow significantly impacts the separation of the boundary layer and skin friction of the airfoil, ultimately affecting its aerodynamic characteristics. The pressure distribution around the surface of NACA0012 has also been computed at several Reynolds number and different attack angles using higher order triangular meshes. Numerical evaluation of these results when compared with the experimental results demonstrates superior accuracy with higher-order finite element mesh. The investigation carried out by higher-order element meshing approach is based on the subparametric transformation of parabolic arcs of triangular element curved at one side. Moreover, the high aspect ratio meshes obtained during discretization of airfoil design have been considered for the analysis. The investigation has yielded results that closely align with experimental data, demonstrating excellent performance. The current efficient analysis of pressure and flow transition is beneficial in interpreting aerodynamic performance and flow simulations for aerospace and computational fluid dynamics applications.

Analysis of the exact solutions of nonlinear coupled Drinfeld–Sokolov–Wilson equation through [formula omitted]-model expansion method

The coupled Drinfeld–Sokolov–Wilson (DSW) equation is a system of nonlinear partial differential equations (NLPDEs) in (1+1)-dimensions that play a fundamental role in soliton theory and integrable systems. Due to its ability to accurately describe wave phenomena in dispersive water waves, coupled DSW equation has wide-ranging applications in fluid dynamics, plasma physics, and mathematical physics. This study investigates the solitary wave solution of coupled DSW equation by using ϕ6-model expansion. This technique reveals the diverse types of solutions, including bright, dark, singular, and periodic singular solitons. The 3D, contour, and 2D plots are also illustrated to demonstrate the physical behavior of the obtained solutions. The findings of this study can contribute to the development of new analytical and numerical tools for solving other nonlinear equations in the future. The inclusion of constraint conditions in the ϕ6-model expansion technique enhances its applicability and reliability, rendering it a valuable approach for investigating nonlinear systems in various scientific domains.

Resonance Soliton, Breather and Interaction Solutions of the Modified Kadomtsev–Petviashvili-II Equation

In this paper, we investigate the modified Kadomtsev–Petviashvili-II (mKP-II) equation, which has important applications in fluid dynamics, plasma physics and electrodynamics. By utilizing the Hirota bilinear method, the N-soliton solutions of the mKP-II equation are obtained. The resonance Y-type soliton, and the interaction between M-resonance Y-type solitons and P-resonance Y-type solitons are constructed by imposing some constraints to the parameters of the N-soliton solutions. Moreover, the novel type of double opening resonance Y-type soliton solutions are obtained by selecting some appropriate parameters in 3-soliton solutions. By making some conjugate assumptions in the parameters, the multiple breathers are presented. Furthermore, the hybrid solutions consisting of multiple breathers and resonance Y-type solitons are investigated. The dynamics of these hybrid solutions are analyzed using both numerical simulations and graphical methods.

Soliton–mean field interaction in Korteweg–de Vries dispersive hydrodynamics

AbstractThe mathematical description of localized solitons in the presence of large‐scale waves is a fundamental problem in nonlinear science, with applications in fluid dynamics, nonlinear optics, and condensed matter physics. Here, the evolution of a soliton as it interacts with a rarefaction wave or a dispersive shock wave, examples of slowly varying and rapidly oscillating dispersive mean fields, for the Korteweg–de Vries equation is studied. Step boundary conditions give rise to either a rarefaction wave (step up) or a dispersive shock wave (step down). When a soliton interacts with one of these mean fields, it can either transmit through (tunnel) or become embedded (trapped) inside, depending on its initial amplitude and position. A topical review of three separate analytical approaches is undertaken to describe these interactions. First, a basic soliton perturbation theory is introduced that is found to capture the solution dynamics for soliton–rarefaction wave interaction in the small dispersion limit. Next, multiphase Whitham modulation theory and its finite‐gap description are used to describe soliton–rarefaction wave and soliton–dispersive shock wave interactions. Lastly, a spectral description and an exact solution of the initial value problem is obtained through the inverse scattering transform. For transmitted solitons, far‐field asymptotics reveal the soliton phase shift through either type of wave mentioned above. In the trapped case, there is no proper eigenvalue in the spectral description, implying that the evolution does not involve a proper soliton solution. These approaches are consistent, agree with direct numerical simulation, and accurately describe different aspects of solitary wave–mean field interaction.