IF 1.9

Fluids Pub Date : 2024-01-06 DOI: 10.3390/fluids9010015

Aldo Tamburrino

引用次数: 0

A GPU-Accelerated Modern Fortran Version of the ECHO Code for Relativistic Magnetohydrodynamics 相对论磁流体动力学 ECHO 代码的 GPU 加速现代 Fortran 版本

IF 1.9

Fluids Pub Date : 2024-01-05 DOI: 10.3390/fluids9010016

Luca Del Zanna, Simone Landi, Lorenzo Serafini, Matteo Bugli, E. Papini

{"title":"A GPU-Accelerated Modern Fortran Version of the ECHO Code for Relativistic Magnetohydrodynamics","authors":"Luca Del Zanna, Simone Landi, Lorenzo Serafini, Matteo Bugli, E. Papini","doi":"10.3390/fluids9010016","DOIUrl":"https://doi.org/10.3390/fluids9010016","url":null,"abstract":"The numerical study of relativistic magnetohydrodynamics (MHD) plays a crucial role in high-energy astrophysics but unfortunately is computationally demanding, given the complex physics involved (high Lorentz factor flows, extreme magnetization, and curved spacetimes near compact objects) and the large variety of spatial scales needed to resolve turbulent motions. A great benefit comes from the porting of existing codes running on standard processors to GPU-based platforms. However, this usually requires a drastic rewriting of the original code, the use of specific languages like CUDA, and a complex analysis of data management and optimization of parallel processes. Here, we describe the porting of the ECHO code for special and general relativistic MHD to accelerated devices, simply based on native Fortran language built-in constructs, especially do concurrent loops, few OpenACC directives, and straightforward data management provided by the Unified Memory option of NVIDIA compilers. Thanks to these very minor modifications to the original code, the new version of ECHO runs at least 16 times faster on GPU platforms as compared to CPU-based ones. The chosen benchmark is the 3D propagation of a relativistic MHD Alfvén wave, for which strong and weak scaling tests performed on the LEONARDO pre-exascale supercomputer at CINECA are provided (using up to 256 nodes corresponding to 1024 GPUs, and over 14 billion cells). Finally, an example of high-resolution relativistic MHD Alfvénic turbulence simulation is shown, demonstrating the potential for astrophysical plasmas of the new GPU-based version of ECHO.","PeriodicalId":12397,"journal":{"name":"Fluids","volume":"86 5","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139450132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Degradation Identification of an EHA Piston Pump by Analysis of Load-Holding States 通过分析负载保持状态识别 EHA 活塞泵的退化情况

IF 1.9

Fluids Pub Date : 2024-01-02 DOI: 10.3390/fluids9010014

Yannick Duensing, Amos Merkel, Katharina Schmitz

引用次数: 0

An Exploratory Wind Tunnel Study of Air Jet Wheel Spoilers 喷气式车轮扰流器的风洞试验研究

IF 1.9

Fluids Pub Date : 2023-12-18 DOI: 10.3390/fluids8120322

Jeff Howell, Daniel Butcher, Martin Passmore

引用次数: 0

Flight Dynamic Characteristics of Wide-Body Aircraft with Wind Gust and Turbulence 有阵风和湍流的宽体飞机的飞行动态特性

IF 1.9

Fluids Pub Date : 2023-12-16 DOI: 10.3390/fluids8120320

Kashif Mehmood, Syed Irtiza Ali Shah, Taimur Ali Shams, M. N. Mumtaz Qadri, Tariq Amin Khan, David Kukulka

{"title":"Flight Dynamic Characteristics of Wide-Body Aircraft with Wind Gust and Turbulence","authors":"Kashif Mehmood, Syed Irtiza Ali Shah, Taimur Ali Shams, M. N. Mumtaz Qadri, Tariq Amin Khan, David Kukulka","doi":"10.3390/fluids8120320","DOIUrl":"https://doi.org/10.3390/fluids8120320","url":null,"abstract":"In this research, a wide-body aircraft was analyzed with critical monitoring of its states, a function of several control inputs (wind gust, turbulence, and microburst). The aerodynamic and stability coefficients of a Boeing 747-200 were obtained from previously published works and 6- DOF equations were formulated. Simulations were conducted for various control inputs to determine the aircraft’s free response, as well as the forced response. In order to understand the nature of the atmosphere, three different models were incorporated, including (i) the Dryden Model, (ii) wind gust, and (iii) microburst. The aircraft was found to be stable in the longitudinal and lateral flight modes, with trim conditions agreeing with published data. For a vertical wind gust of −10 ft/s, the AoA and pitch rate were observed to oscillate sinusoidally and became stable with new trim conditions. These states were found to regain trim conditions once the gust was removed. In the case of 3D gust, it was found that the longitudinal modes achieved a new trim condition through Phugoid oscillations, whereas the lateral modes underwent short-period oscillations. For the case of turbulence, random fluctuations were observed for trim conditions with no unstable behavior. When considering the microburst case, it was found that the aircraft initially gained altitude in the region of the headwind; this was followed by a sharp descent under the influence of a vertical velocity component.","PeriodicalId":12397,"journal":{"name":"Fluids","volume":"101 10‐12","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138966821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Task-Driven Path Planning for Unmanned Aerial Vehicle-Based Bridge Inspection in Wind Fields 基于无人飞行器的风场桥梁检测任务驱动路径规划

IF 1.9

Fluids Pub Date : 2023-12-16 DOI: 10.3390/fluids8120321

Yonghu Wang, Chengcheng Duan, Xinyu Huang, Juan Zhao, Ran Zheng, Haiping Li

{"title":"Task-Driven Path Planning for Unmanned Aerial Vehicle-Based Bridge Inspection in Wind Fields","authors":"Yonghu Wang, Chengcheng Duan, Xinyu Huang, Juan Zhao, Ran Zheng, Haiping Li","doi":"10.3390/fluids8120321","DOIUrl":"https://doi.org/10.3390/fluids8120321","url":null,"abstract":"Using unmanned aerial vehicles (UAVs) for bridge inspection is becoming increasingly popular due to its ability to improve efficiency and ensure the safety of monitoring personnel. Compared to traditional manual monitoring methods, UAV inspections are a safer and more efficient alternative. This paper examines the impact of meteorological conditions on UAV-based bridge monitoring during specific tasks, with the aim of enhancing the safety of the UAV’s costly components. The wake vortex behind a bridge structure can vary over time due to airflow, which can have a direct impact on the safety of UAV flights. To assess this impact, numerical analysis is conducted based on monitoring requirements specific to different tasks, taking into account wind speed, wind direction, and air temperature. In order to optimize UAV trajectory, it is important to consider the wake vortex intensity and its associated influence region, which can pose a potential danger to UAV flight. Additionally, the analysis should take into account the aerodynamic effects of different types of bridge columns on the wake vortex. An optimization algorithm was utilized to optimize the trajectory of a UAV during bridge inspections within the safe region affected by wind fields. This resulted in the determination of an effective and safe flight path. The study reveals that varying wind speeds have an impact on the safe flight zone of UAVs, even if they are below the operational requirements. Therefore, when monitoring bridges using UAVs, it is important to take into account the influence of meteorological conditions. Furthermore, it was observed that the flight path of UAVs during square cylinder column monitoring is longer and more time-consuming than round cylinder column monitoring. Determining an effective UAV inspection path is crucial for completing bridge monitoring tasks in windy conditions, establishing bridge inspection standards, and developing the Intelligent Bridge Inspection System (IBIS).","PeriodicalId":12397,"journal":{"name":"Fluids","volume":"7 10","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138968037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Demonstrating the Kelvin-Helmholtz Instability Using a Low-Cost Experimental Apparatus and Computational Fluid Dynamics Simulations 利用低成本实验设备和计算流体力学模拟展示开尔文-赫尔姆霍兹不稳定性

IF 1.9

Fluids Pub Date : 2023-12-12 DOI: 10.3390/fluids8120318

Melissa M. Gibbons, Dillon Muldoon, Imane Khalil

{"title":"Demonstrating the Kelvin-Helmholtz Instability Using a Low-Cost Experimental Apparatus and Computational Fluid Dynamics Simulations","authors":"Melissa M. Gibbons, Dillon Muldoon, Imane Khalil","doi":"10.3390/fluids8120318","DOIUrl":"https://doi.org/10.3390/fluids8120318","url":null,"abstract":"A Kelvin-Helmholtz instability is formed when two fluids of different densities exert a shear on one another at their interface when flowing in opposite directions. This paper presents a step-by-step guide for the design of a low-cost, small-scale, experimental tilt tube apparatus and a corresponding computational fluid dynamics (CFD) model that can be used to introduce the Kelvin-Helmholtz instability to undergraduate mechanical engineering students in several courses. A thermal-fluids laboratory course is taken by our fourth-year mechanical engineering students, and the overall variety of experiments has been limited by the cost of commercial teaching equipment. The tilt tube apparatus allows students to induce and record the Kelvin-Helmholtz instability, and no ongoing costs are involved in incorporating this experiment into the course. In our introductory CFD course, students perform CFD simulations as part of the design and analysis process. Developing a two-dimensional (2D) CFD model with two different fluids is well within their capabilities after completing initial software and simulation tutorial exercises and homework. Representative experiments were conducted with fresh water and salt water of different densities, and results showed that both the amplitude of the waves and the amount of time the instability was visible decreased with increasing salt water salinity. Results from a 2D CFD model developed in Ansys Fluent exhibited the same trends as the experimental data.","PeriodicalId":12397,"journal":{"name":"Fluids","volume":"11 11","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139007553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Mathematical Model of Blood Loss during Renal Resection 肾切除术中失血量的数学模型

IF 1.9

Fluids Pub Date : 2023-12-10 DOI: 10.3390/fluids8120316

James Cowley, Xichun Luo, Grant D. Stewart, Wenmiao Shu, A. Kazakidi

{"title":"A Mathematical Model of Blood Loss during Renal Resection","authors":"James Cowley, Xichun Luo, Grant D. Stewart, Wenmiao Shu, A. Kazakidi","doi":"10.3390/fluids8120316","DOIUrl":"https://doi.org/10.3390/fluids8120316","url":null,"abstract":"In 2021, approximately 51% of patients diagnosed with kidney tumors underwent surgical resections. One possible way to reduce complications from surgery is to minimise the associated blood loss, which, in the case of partial nephrectomy, is caused by the inadequate repair of branching arteries within the kidney cut during the tumor resection. The kidney vasculature is particularly complicated in nature, consisting of various interconnecting blood vessels and numerous bifurcation, trifurcation, tetrafurcation, and pentafurcation points. In this study, we present a mathematical lumped-parameter model of a whole kidney, assuming a non-Newtonian Carreau fluid, as a first approximation of estimating the blood loss arising from the cutting of single or multiple vessels. It shows that severing one or more blood vessels from the kidney vasculature results in a redistribution of the blood flow rates and pressures to the unaltered section of the kidney. The model can account for the change in the total impedance of the vascular network and considers a variety of multiple cuts. Calculating the blood loss for numerous combinations of arterial cuts allows us to identify the appropriate surgical protocols required to minimise blood loss during partial nephrectomy as well as enhance our understanding of perfusion and account for the possibility of cellular necrosis. This model may help renal surgeons during partial organ resection in assessing whether the remaining vascularisation is sufficient to support organ viability.","PeriodicalId":12397,"journal":{"name":"Fluids","volume":"60 15","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138982467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Constructal-Theory-Based Methodology to Determine the Configuration of Empty Channels Used in the Resin Impregnation of a Square Porous Plate 基于构造理论的方法确定方形多孔板树脂浸渍过程中所用空槽的构造

IF 1.9

Fluids Pub Date : 2023-12-10 DOI: 10.3390/fluids8120317

G. M. C. Magalhães, J. A. Souza, E. D. dos Santos

{"title":"A Constructal-Theory-Based Methodology to Determine the Configuration of Empty Channels Used in the Resin Impregnation of a Square Porous Plate","authors":"G. M. C. Magalhães, J. A. Souza, E. D. dos Santos","doi":"10.3390/fluids8120317","DOIUrl":"https://doi.org/10.3390/fluids8120317","url":null,"abstract":"Liquid composite molding techniques are largely used to produce pieces such as truck cabins or wind turbine blades. The liquid resin infusion processes use a network of injection channels to improve the resin flow through a porous-reinforced medium. The present numerical study predicts the positioning of empty channels by applying constructal theory to an idealized problem. The channels’ position and size were not predefined but instead constructed (made to grow) from an elemental channel. Two strategies were tested for channel growth: each new elemental channel was placed next to the region with the lowest or highest resistance to resin flow. The geometric configuration of the channels was constructed using a control function instead of using pre-defined shapes. The conservation of mass and momentum and an additional transport equation for the resin volume fraction were solved using the finite volume method. The volume of the fluid model was used for the treatment of the multiphase flow (air + resin). The growth of an empty channel with the lowest resistance strategy led to a decrease in the injection time and waste of resin. The size (resolution) of the elemental channel also affected the performance indicators and geometric configuration of the injection channels.","PeriodicalId":12397,"journal":{"name":"Fluids","volume":"10 7","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138982194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Identification of Local Isotropic Turbulence Conditions in Various Bubble Columns Based on Several Reliable Parameters 基于几个可靠参数识别各种气泡柱中的局部各向同性湍流条件

IF 1.9

Fluids Pub Date : 2023-12-04 DOI: 10.3390/fluids8120314

S. Nedeltchev

{"title":"Identification of Local Isotropic Turbulence Conditions in Various Bubble Columns Based on Several Reliable Parameters","authors":"S. Nedeltchev","doi":"10.3390/fluids8120314","DOIUrl":"https://doi.org/10.3390/fluids8120314","url":null,"abstract":"Bubble columns (BCs) are widely used in the chemical industry. In many industrial applications, these important gas-liquid contactors operate in a churn-turbulent flow regime. In principle, it is essential to determine the operating conditions in every BC reactor, in which local isotropic turbulence is established. In this work, it was demonstrated that several different parameters (Kolmogorov entropy, correlation dimension and novel hybrid index) follow a monotonic decreasing trend. This finding could be explained by the constantly increasing coalesced bubble size, which brings more order into the gas-liquid system and thus any entropic or chaotic parameter should decrease with the increase in the superficial gas velocity Ug. The profiles of the new parameters in various gas-liquid systems were studied. They were extracted from different pressure signals (gauge or absolute). In this research, BCs of different diameter and equipped with different gas distributors were used. It was demonstrated that the studied parameters could be successfully correlated with the length scale of the micro eddies and thus the Ug range of applicability of the local isotropic turbulence theory under various operating conditions was indirectly determined. The overall gas holdup profiles were analyzed and, based on the exponent of the Ug value, it was found that in the aqueous solutions of alcohols studied, the conditions in the bubble bed (BB) are homogeneous, whereas in the air-tap water system aerated in different BCs, the conditions in the BB are heterogeneous. This result implies that the local isotropic turbulence conditions predominate mainly around the corresponding measurement positions.","PeriodicalId":12397,"journal":{"name":"Fluids","volume":"81 2","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138604548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

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