Yuli D. Chashechkin, Andrey Y. Ilinykh^*

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.4, pp. 801-811, 2020, DOI:10.32604/fdmp.2020.09168 - 11 August 2020

Abstract The interaction of a falling drop (diluted aqueous solution of ink in various concentrations) with a target fluid (partially degassed tap water) has been tracked by means of high-resolution video recording and photography. The experimental setup has carefully been prepared in order to preserve the axial symmetry of initial conditions. Three regimes of interaction have been identified accordingly (depending on the drop velocity as controlled by the distance of fall): rapid droplet coalescence, rebound with the conservation of the drop volume and shape, and partial coalescence. Previous findings are recovered and confirmed, and enriched with More >

Yuli D. Chashechkin^*

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.4, pp. 773-800, 2020, DOI:10.32604/fdmp.2020.09001 - 11 August 2020

Abstract The structure of the flow and the acoustic signals generated by the impact of a freely falling drop of water with an underlying quiescent fluid have been investigated for droplets having diameter 0.5 cm and a contact velocity in the range 1.5 < U < 5 m/s. The experimental study has been supported by high-resolution videos of the flow (as seen from above and from the side). The evolution of ejecta, spikes, droplets spray, cavity, splash, secondary cavity, streamer, secondary droplets and sequence of capillary waves is reported accordingly. In particular, perturbations of the smoothed… More >

Aleksandr Shiryaev^*

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.4, pp. 761-771, 2020, DOI:10.32604/fdmp.2020.09010 - 11 August 2020

Abstract The problem relating to the small-amplitude free capillary oscillations of an encapsulated spherical drop is solved theoretically in the framework of asymptotic methods. Liquids are supposed to be inviscid and immiscible. The formulas derived are presented for different parameters of the inner and outer liquids, including densities, thickness of the outer liquid layer, and the surface and interfacial tension coefficients. The frequencies of oscillation of the encapsulated drop are studied in relation to several “modes” which can effectively be determined in experiments by photo and video analysis. The results are presented in terms of oscillation More >

V. E. Prokhorov^*

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.4, pp. 737-746, 2020, DOI:10.32604/fdmp.2020.08988 - 11 August 2020

Abstract The collision of droplets with a water surface is being actively developed in the interests of many applied problems—transfer of matter through the ocean-atmosphere boundary, underwater acoustic noise of the marine environment, measurement of precipitation intensity, various technologies, and much more. One of the research priorities is acoustic radiation, in particular, shock sound arising at the moment a drop contacts the surface. The impact of the drop is preceded by processes that affect the shape of the drop, because of which it noticeably deviates from the spherical one. As a result, the final (contact) velocity More >

Andrey Y. Ilinykh^*

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.4, pp. 723-735, 2020, DOI:10.32604/fdmp.2020.08987 - 11 August 2020

Abstract The distribution of material resulting from the impact of a freely falling drop with a target liquid has been studied by photo and video registration methods. Different cases have been investigated by considering drops made of aqueous solutions (ink, salt, acid) and including fine solid particles (i.e., suspensions). New features have been observed in terms of flow dynamics and thin components produced as a result of the impact (such as banded elements, ligaments, and vortices at the surface of the liquid). In particular, the characteristics of emerging netlike structures have been found to depend on More >

Jinxing Niu^{1, *}, Yajie Jiang¹, Yayun Fu¹, Tao Zhang¹, Nicola Masini²

CMC-Computers, Materials & Continua, Vol.65, No.1, pp. 807-816, 2020, DOI:10.32604/cmc.2020.011044 - 23 July 2020

Abstract Video surveillance system is used in various fields such as transportation and social life. The bad weather can lead to the degradation of the video surveillance image quality. In rainy environment, the raindrops and the background are mixed, which lead to make the image degradation, so the removal of the raindrops has great significance for image restoration. In this article, after analyzing the inter-frame difference method in detecting and removing raindrops, a background difference method is proposed based on Gaussian model. In this method, the raindrop is regarded as a moving object relative to the… More >

Xiangyu Gao, Weidong Yang^*, Hongxuan Xian, Xiyuan Tu, Yuanyuang Wang^*

CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.1, pp. 227-241, 2020, DOI:10.32604/cmes.2020.09923 - 19 June 2020

Abstract This paper studies the binder droplet injection process in the 3DP technique. The mathematical model of the binder penetration process for multi-nozzle and multi-layer in 3DP technique is established, by using the conservation Level set method. According to the two-dimensional plane model of three-dimensional spatial structure of sand bed, the construction method of an equivalent cylindrical mapping infiltration model is proposed to represent the porosity of the model in the two-dimensional plane, which is exactly the same as that in the three-dimensional space, as well as closer to the arrangement of the three-dimensional space, and… More >

Tianyu Xu, Lixiang Zhang^*

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.3, pp. 525-536, 2020, DOI:10.32604/fdmp.2020.09618 - 25 May 2020

Abstract In this article, computational fluid dynamics (CFD) are used to explore the dynamics of water transport inside the pitted thickening of a plant xylem vessel. A pitted thickening model combined with the Bernoulli equation is used to analyze the influence of various factors (namely, the inner diameter, thickening width, thickening height, thickening spacing, number of laps and adjacent pit axial rotation). The pressure drop and the flow resistance coefficient are the variable parameters for our analysis. The results show that these two parameters are proportional to the thickening height and thickening width, and inversely proportional More >

Yushan Liu^1,2, Yubin Su³, Zhenhua Wu⁴, Wei Luo^1,2, Ruiquan Liao^1,2,*

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.3, pp. 475-488, 2020, DOI:10.32604/fdmp.2020.08896 - 25 May 2020

Abstract The lifting efficiency and stability of gas lift well are affected by the socalled slippage-loss effect in gas-liquid two-phase flow. The existing studies on this subject have generally been based on vertical and horizontal wells. Only a few of them have considered inclined pipes. In the present work a new focused study is presented along these lines. More specifically, we use the non-slip pressure drop model with Flanigan’s fluctuation correction coefficient formula (together with the parameters of slippage density, slippage pressure drop and slippage ratio) to analyze the influence of the inclination angle on slippage… More >

Xiaoya Feng^{1, 2}, Wei Luo^{1, 2, *}, Yu Lei³, Yubin Su⁴, Zhigang Fang³

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.2, pp. 339-358, 2020, DOI:10.32604/fdmp.2020.08564 - 21 April 2020

Abstract Gas-liquid two-phase flow is ubiquitous in the process of oil and gas exploitation, gathering and transportation. Flow pattern, liquid holdup and pressure drop are important parameters in the process of gas-liquid two-phase flow, which are closely related to the smooth passage of the two-phase fluid in the pipe section. Although Mukherjee, Barnea and others have studied the conventional viscous gas-liquid two-phase flow for a long time at home and abroad, the overall experimental scope is not comprehensive enough and the early experimental conditions are limited. Therefore, there is still a lack of systematic experimental research… More >