Open Access

ARTICLE

Antonio Esposito¹, Marcello Lappa^2,*, Rocco Pagliara³, Gennaro Spada¹
FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.2, pp. 189-203, 2022, DOI:10.32604/fdmp.2022.019605
Abstract The ability to measure the very high heat fluxes that typically occur during the hypersonic re-entry phase of space vehicles is generally considered a subject of great importance in the aerospace field. Most of the sensors used for these measurements need to be checked periodically and re-calibrated accordingly. Another bottleneck relates to the need to procure thermal sources that are able to generate reliable reference heat fluxes in the range between 100 and 1000 kW/m² (as order of magnitude). In the present study, a method is presented by which, starting from a calibration system with a capacity of approximately 500 kW/m² only,… More >

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ARTICLE

Abdulmajeed D. Aldabesh¹, P. K. Pattnaik², S. Jena³, S. R. Mishra⁴, Mouna Ben Henda⁵, Iskander Tlili^5,*
FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.2, pp. 205-222, 2022, DOI:10.32604/fdmp.2022.017899
Abstract Free convection of a viscous electrically conducting liquid past a vertical stretching surface is investigated in the presence of a transverse magnetic field. Natural convection is driven by both thermal and solutal buoyancy. The original partial differential equations governing the problem are turned into a set of ordinary differential equations through a similar variables transformation. This alternate set of equations is solved through a Differential Transform Method (DTM) and the Pade approximation. The response of the considered physical system to the non-dimensional parameters accounting for the relative importance of different effects is assessed considering different situations. More >

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863

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ARTICLE

G. Boopathy^1,2,*, K. Gurusami¹, M. Chinnapandian³, K. R. Vijayakumar⁴
FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.2, pp. 223-232, 2022, DOI:10.32604/fdmp.2022.018225
（This article belongs to this Special Issue: Materials and Nanotechnology: New Challenges)
Abstract In this research study, the mechanical properties of several Polymer matrix composites are investigated. These composites are multi-phase materials in which reinforcing materials are properly mixed with a polymer matrix. More precisely, Nylon 6 reinforced with 5, 15 and 25 wt. % of silicon carbide (SiC) and Nylon 6 reinforced with 5, 15 and 25 wt. % of boron carbide (B₄C), prepared by means of an injection moulding process at three different injection pressures are considered. Specific attention is paid to the tensile and impact strength of these composites. The Taguchi technique is used to optimize the process parameters such as reinforcement… More >

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ARTICLE

Xuewen Cao¹, Ni Xiong¹, Jian Li², Zhenqiang Xie¹, Xuerui Zang¹, Jiang Bian^1,*
FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.2, pp. 233-241, 2022, DOI:10.32604/fdmp.2022.018505
（This article belongs to this Special Issue: Advanced Oil and Gas Transportation and Treatment Technologies)
Abstract The influence of the material stress state induced by internal and external forces on the erosion rate of pipelines has rarely been investigated in the literature. In order to fill this gap, using a tensile tester machine, a two–phase gas–solid particles jet erosion test was carried out considering a 316L stainless steel under different tensile stresses and different erosion angles. The results show that: 1) In the elastic range, with the increase of stress, the erosion rate manifests a rising trend; 2) In the metal plastic range, the increase of stress leads to a decrease of the erosion rate; 3)… More >

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ARTICLE

Jianhui Yang¹, Kai Shen¹, Shoudong Pan², Shuren Wang^3,*, Zhengsheng Zou³
FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.2, pp. 243-255, 2022, DOI:10.32604/fdmp.2022.016677
（This article belongs to this Special Issue: Advanced Materials, Processing and Testing Technology)
Abstract The large deformation of soft rock tunnel is one of the key problems to be overcome in the tunnel construction stage. In the present study, the deformation mechanism of a representative tunnel and some related countermeasures are investigated using field tests and engineering geological analysis. Owing to the scarce performances of methods based on other criteria such as small pipe spacing, anchor bolt length and steel frame spacing, a new support scheme is implemented and optimized. Results show that shear failure and bedding sliding are produced under high horizontal stress conditions. The low strength of the surrounding rock results in… More >

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993

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ARTICLE

Zuoming Yin^1,*, Xuguang Wang², Desheng Wang¹, Zhiheng Dang¹, Jianfeng Shao³
FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.2, pp. 257-269, 2022, DOI:10.32604/fdmp.2022.017915
（This article belongs to this Special Issue: EFD and Heat Transfer III)
Abstract The present study considers the so-called air deck blasting, one of the most commonly used techniques for the improvement of blasting efficiency in mining applications. In particular, it aims to improve the operating conditions of large-scale equipment, increase the efficiency of the slope enlarging process, and reduce the mining cost. These objectives are implemented through a two-fold approach where, first, a program for slope enlarging based on the middle air-deck charge blasting-loosening technology is proposed, and second, the physical mechanism responsible for the stress wave attenuation in the rock is analyzed in the framework of a Holmquist–Johnson–Cook constitutive model. Field… More >

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940

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ARTICLE

Pengfei Wang^1,2, Xiangyang Zhang^1,*
FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.2, pp. 271-283, 2022, DOI:10.32604/fdmp.2022.017882
（This article belongs to this Special Issue: EFD and Heat Transfer III)
Abstract A mixture of fault gouge and rubble taken out from a fault zone is used to prepare a S-RM (Soil-Rock Mixture) sample with rock block proportions of 20%, 30%, 40%, 50%, 60% and 70%, respectively. A GDS triaxial test system is used accordingly to measure the seepage characteristics of such samples under different loading and unloading confining pressures in order to determine the variation law of the permeability coefficient. The test results show that: (1) The permeability coefficient of the S-RM samples decreases as the pressure increases, and the decrease rate of this coefficient in the initial stage of confining… More >

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ARTICLE

Fang Jin^*, Dong Zhou, Liying Zhu
FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.2, pp. 285-302, 2022, DOI:10.32604/fdmp.2022.017593
（This article belongs to this Special Issue: EFD and Heat Transfer III)
Abstract The purpose is to study the microstructure and macroscopic fluid-dynamic behavior of soft soil after it has been subjected to a seepage consolidation procedure. First, the microscopic pore structure of soft clay is quantitatively studied by a scanning electron microscope technique. Second, the average contact area rate of soil particles is obtained employing statistical analysis applied to microscopic images of soft soil, and the macroscopic porosity of soft clay is determined through an indoor geotechnical test. Finally, mathematical relationships are introduced by fitting the results of the test. The results show that the unmodified empirical equation for the permeability coefficient… More >

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851

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ARTICLE

Xiangxi Du^1,*, Muyun Liu², Yanhua Sun¹
FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.2, pp. 303-312, 2022, DOI:10.32604/fdmp.2022.016242
（This article belongs to this Special Issue: EFD and Heat Transfer III)
Abstract The computational fluid dynamics (CFD) technology is analyzed and calculated utilizing the turbulence model and multiphase flow model to explore the performance of internal circulating fluidized beds (ICFB) based on CFD. The three-dimensional simulation method can study the hydrodynamic properties of the ICFB, and the performance of the fluidized bed is optimized. The fluidization performance of the ICFB is improved through the experimental study of the cross-shaped baffle. Then, through the cross-shaped baffle and funnel-shaped baffle placement, the fluidized bed reaches a coupled optimization. The results show that CFD simulation technology can effectively improve the mass transfer efficiency and performance… More >

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1005

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ARTICLE

Meng Song^1,*, Yuncai Liu², Zhen Wang¹
FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.2, pp. 313-327, 2022, DOI:10.32604/fdmp.2022.017737
（This article belongs to this Special Issue: EFD and Heat Transfer III)
Abstract The purpose of the study is to implement a new model based on the Navier-Stokes equations for the characterization of landslide sediments interacting with a moving fluid. The model is implemented by combining Hypermesh, the LS-DYNA software and MATLAB. The results show that the main factors affecting the permeability of landslide sediments are the genetic mechanism, the structure and composition of materials, material lithology, and stress. The characteristics and mechanism of permeability changes are determined by adjusting the water levels of fluids. It is found that the permeability of landslide sediments increases at the front and decreases in the middle… More >

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904

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ARTICLE

Yajuan Jia¹, Lisha Shang¹, Jiangping Nan¹, Guangping Hu², Zhigang Fang^3,4,*
FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.2, pp. 329-344, 2022, DOI:10.32604/fdmp.2022.017734
（This article belongs to this Special Issue: EFD and Heat Transfer III)
Abstract The flow past a fixed single transmission conductor and the related heat transfer characteristics are investigated using computational fluid dynamics and a relevant turbulence model. After validating the method through comparison with relevant results in the literature, this thermofluid-dynamic problem is addressed considering different working conditions. It is shown that the resistance coefficient depends on the Reynolds number. As expected, the Nusselt number is also affected by Reynolds number. In particular, the Nusselt number under constant heat flux is always greater than that under a constant wall temperature. More >

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919

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ARTICLE

Jian Song^*
FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.2, pp. 345-354, 2022, DOI:10.32604/fdmp.2022.017382
（This article belongs to this Special Issue: EFD and Heat Transfer III)
Abstract Computational Fluid Dynamics is used to assess the thermal (heat transfer) performances of an automobile engine considering different grille opening and closing degrees. For this purpose the entire vehicle is modelled and three fundamental aspects are examined, namely, the open area of the air intake grille, the position of the upper and lower grilles and their shape. The results show that the opening area and position of the grille have some influence also on the aerodynamic characteristics of the automobile. With an increase in the opening angle of the grille, the C_D (Drag Coefficient) value of the whole vehicle becomes… More >

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ARTICLE

Yi Tu¹, Yu Zeng^2,*
FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.2, pp. 355-370, 2022, DOI:10.32604/fdmp.2022.018423
Abstract Onboard air separation devices, based on hollow fiber membranes, are traditionally used for the optimization of aircraft fuel tank inerting systems. In the present study, a set of tests have been designed and executed to assess the air separation performances of these systems for different air inlet temperatures (70°C∼110°C), inlet pressures (0.1∼0.4 MPa), volume flow rates of nitrogen-enriched air (NEA) (30∼120 L/min) and flight altitudes (1.5∼18 km). In particular, the temperature, pressure, volume flow rate, and oxygen concentration of air, NEA and oxygen-enriched air (OEA) have been measured. The experimental results show that the oxygen concentration of NEA, air separation coefficient, and… More >

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ARTICLE

Yueli Feng^1,2, Yuetian Liu^1,2,*, Xiaolong Mao^1,2, Jian Chen^1,2
FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.2, pp. 371-393, 2022, DOI:10.32604/fdmp.2022.017534
Abstract This study clarifies the seepage characteristics of complex fractured pressure-sensitive reservoirs, and addresses a common technological problem, that is the alteration of the permeability degree of the reservoir bed (known to be responsible for changes in the direction and velocity of fluid flows between wells). On the basis of a new pressure-sensitive equation that considers the fracture directional pressure-sensitive effect, an oil-gas-water three-phase seepage mathematical model is introduced, which can be applied to pressure-sensitive, full-tensor permeability, ultralow-permeability reservoirs with fracture-induced anisotropy. Accordingly, numerical simulations are conducted to explore the seepage laws for ultralow-permeability reservoirs. The results show that element patterns… More >

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ARTICLE

Yueli Feng^1,2, Yuetian Liu^1,2,*, Jian Chen^1,2, Xiaolong Mao^1,2
FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.2, pp. 395-415, 2022, DOI:10.32604/fdmp.2022.018141
Abstract Stress sensitivity is a very important index to understand the seepage characteristics of a reservoir. In this study, dedicated experiments and theoretical arguments based on the visualization of porous media are used to assess the effects of the fracture angle, spacing, and relevant elastic parameters on the principal value of the permeability tensor. The fracture apertures at different angles show different change rates, which influence the relative permeability for different sets of fractures. Furthermore, under the same pressure condition, the fractures with different angles show different degrees of deformation so that the principal value direction of permeability rotates. This phenomenon… More >

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874

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ARTICLE

Mingren Shao¹, Chunpeng Wang¹, Degui Wang¹, Wenbo Mei¹, Mingjie Li¹, Hao Yang^2,*
FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.2, pp. 417-430, 2022, DOI:10.32604/fdmp.2022.018012
Abstract Detailed information is provided for the design and construction of nitrogen drilling in a coal seam. Two prototype wells are considered. The Guo model is used to calculate the required minimum gas injection rate, while the Finnie, Sommerfeld, and Tulsa models are exploited to estimate the ensuing erosion occurring in pipe strings. The calculated minimum gas injection rates are 67.4 m³/min (with water) and 49.4 m³/min (without water), and the actual field of use is 90–120 m³/min. The difference between the calculated injection pressure and the field value is 6.5%–15.2% (formation with water) and 0.65%–7.32% (formation without water). The results… More >

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992

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ARTICLE

Tiankui Guo^1,*, Zhilin Luo¹, Shanbo Mou², Ming Chen¹, Yuanzhi Gong³, Jianhua Qin⁴
FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.2, pp. 431-447, 2022, DOI:10.32604/fdmp.2022.017861
Abstract Although the dynamics of proppant (small ceramic balls used to prevent opened fractures from closing on the release of pressure) have been the subject of several numerical studies over recent years, large-scale inclined fractures exist in unconventional reservoirs for which relevant information is still missing. In the present study, this problem is investigated numerically considering the influence of several relevant factors such as the fracture roughness, inclination, the proppant particle size, the injection rate and the fluid viscosity. The results show that a rough wall enables the proppant to travel farther and cover larger areas. The inclination angle has little… More >

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REVIEW

Pengfei Ju^1,2,*, Mingrui Li^3,4, Jingying Wang^3,4
FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.2, pp. 449-462, 2022, DOI:10.32604/fdmp.2022.018035
（This article belongs to this Special Issue: Recent Advances in Fluid Mechanics and Thermal Sciences)
Abstract

Computational fluid dynamics (CFD) has become the main method for the prediction of the properties of the external wind environment in cities and other urban contexts. A review is presented of the existing literature in terms of boundary conditions, building models, computational domains, computational grids, and turbulence models. Some specific issues, such as the accuracy/computational cost ratio and the exploitation of existing empirical correlations, are also examined.

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ARTICLE

Jiawei Shi¹, Shuai Ge¹, Xiaozhen Sheng^2,*
FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.2, pp. 463-480, 2022, DOI:10.32604/fdmp.2022.017508
Abstract In order to understand the mechanism by which a pantograph can generate aerodynamic noise and grasp its far-field characteristics, a simplified double-strip pantograph is analyzed numerically. Firstly, the unsteady flow field around the pantograph is simulated in the frame of a large eddy simulation (LES) technique. Then the location of the main noise source is determined using surface fluctuating pressure data and the vortex structures in the pantograph flow field are analyzed by means of the Q-criterion. Based on this, the relationship between the wake vortex and the intensity of the aerodynamic sound source on the pantograph surface is discussed.… More >

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760

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ARTICLE

Wei Chen^1,2, Zhaofeng Guo^3,4,*, Hongda Feng^3,4, Sheng Hu^1,2, Ling Lu^1,2, Chuanmin Chen^3,4, Xiaowen Wu^1,2, Hao Cao^1,2
FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.2, pp. 481-496, 2022, DOI:10.32604/fdmp.2022.015746
Abstract This study investigates a dual-cavity resonant composite sound-absorbing structure based on a micro-perforated plate. Using the COMSOL impedance tube model, the effects of various structural parameters on sound absorption and sound insulation performances are analyzed. Results show that the aperture of the micro-perforated plate has the greatest influence on the sound absorption coefficient; the smaller the aperture, the greater is this coefficient. The thickness of the resonance plate has the most significant influence on the sound insulation and resonance frequency; the greater the thickness, the wider the frequency domain in which sound insulation is obtained. In addition, the effect of… More >

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