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Theoretical & Applied Mechanics Letters 2020年第5期10卷 354-365页

作者： N.Brahmi a.hadjadj Normandie University Institut National des Sciences Appliquées of RouenCNRSCORIA76000 RouenFrance

This paper deals with a numerical study of weak shock-waves propagation and their attenuation in channel flow having different heights and exhibiting a hollow circular cavities with different depths and diffraction angles *** effect of initial diffraction angle and cavity depth on the shock mitigation is investigated.A better shock attenuation is achieved with diffraction angle by a factor of approximately 17%in terms of shock-Mach number and 38%in terms of total *** obtained results show also,in addition to the initial diffraction angle and cavity depth,the importance of reducing the channel heights as well as the position of the reduced section in achieving an optimal shock-wave *** presence of a cavity inside the channel helps to attenuate faster the shock *** underlying physics relies on the shock diffraction phenomenon that generates large amount of vortical structures capable of dissipating part of the shock energy by inducing a pressure loss behind it.A subtle arrangement of channel position/height and a cavity location leads to an efficient pressure attenuation by approximately a factor of 57%forMs=1.6 and 16%for Ms=1.1..

关键词： Shock diffraction Shock reflection Shock attenuation Vortex generation

含激波的湍流流动高精度大涡数值模拟方法（英文）

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空气动力学学报 2016年第2期34卷 190-203页

作者： D.V.Kotov H.C.Yee A.Wray a.hadjadj B.Sjogreen Center for Turbulence Research Stanford UniversityStanfordCA 94305USA NASA Ames Research Center Moffett FieldCA94035USA CORIA UMR 6614&-INSA de Rouen 76800 St-Etienne du RouvrayFrance Lawrence Livermore National Laboratory Box 808L-422LivermoreCA 94551USA

针对采用亚格子模型进行含激波的湍流流动模拟时会面临激波附近的精度损失问题,考虑从通过亚格子模型以及数值模拟方法两方面的改进来实现湍流流动大涡模拟的精度提高。大涡模拟采用了Yee及Sjgreen(2009)提出的高阶低耗散方法。该方... 详细信息

针对采用亚格子模型进行含激波的湍流流动模拟时会面临激波附近的精度损失问题,考虑从通过亚格子模型以及数值模拟方法两方面的改进来实现湍流流动大涡模拟的精度提高。大涡模拟采用了Yee及Sjgreen(2009)提出的高阶低耗散方法。该方法采用自适应的流场探测器以控制计算中所需区域的数值耗散,并考虑对动力学模型采用在激波位置使用Sagaut和Germano(2005)提出的单边亚格子过滤器和(或)直接禁用亚格子项等方法加以改进。对于标准的马赫数1.5和3条件下的激波-湍流干扰问题,上述新方法相较于全区域采用亚格子模型的方法均表现出了相似的精度提升。同时实现的数值精度改进方案采用了Harten的亚单元分辨过程来定位和锐化激波,并在精确激波位置附近的网格点处采用了单边测试滤波。

关键词：高阶低耗散格式 Germao模型大涡模拟滤波直接数值模拟方法亚单元分辨格式激波湍流干扰

New model for standpipe pressure prediction while drilling using Group Method of Data Handling

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Petroleum 2022年第2期8卷 210-218页

作者： Mohamed Riad Youcefi Ahmed hadjadj Farouk Said Boukredera Laboratory of Petroleum Equipment’s Reliability and Materials Faculty of Hydrocarbons and ChemistryUniversity M’hamed Bougara of BoumerdesAvenue de l’Independance35000BoumerdesAlgeria

The continuous evaluation of the measured Stand Pipe Pressure(SPP)against a modeled SPP value in real-time involves the automatic detection of undesirable drilling events such as drill string washouts and mud pump *** theoretical and experimental studies have been established to calculate the friction pressure losses using different rheological models and based on an extension of pipe flow correlations to an annular ***,it would not be feasible to employ these models for real-time applications since they are limited to some conditions and intervals of application and require input parameters that might not be available in real-time on each *** this study,The Group Method of Data Handling(GMDH)is applied to develop a trustworthy model that can predict the SPP in real-time as a function of mud flow,well depth,RPM and the Fan VG viscometer reading at 600 and 300 *** order to accomplish the modeling task,3351 data points were collected from two wells from Algerian *** and statistical assessment criteria disclosed that the model predictions are in excellent agreement with the experimental data with a coefficient of determination of 0.9666 and an average percent relative error less than 2.401%.Furthermore,another dataset(1594 data points)from well-3 was employed to validate the developed correlation for *** obtained results confirmed that the proposed GMDH-SPP model can be applied in real-time to estimate the SPP with high ***,it was found that the proposed GMDH correlation follows the physically expected trends with respect to the employed input ***,the findings of this study can help for the early detection of downhole problems such as drill string washout,pump failure,and bit balling.

关键词： Stand pipe pressure GMDH Drilling Mud flow Real-time monitoring Drill string washouts

Particles-induced turbulence: A critical review of physical concepts,numerical modelings and experimental investigations

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Theoretical & Applied Mechanics Letters 2020年第4期10卷 241-248页

作者： Guodong Gai Abdellah hadjadj Sergey Kudriakov Olivier Thomine DEN-DM2S-STMF CEAUniversitéParis-SaclayFrance University of Normandy INSACORIA UMR-6614 CNRS76000 RouenFrance

The presence of solid particles or water droplets in continuous fluid flow can either induce turbulence attenuation or amplification. The modification of the state of the turbulence depends on the characteristics of the particles, such as volume fraction, mean diameter, mass density, or carrier phase flow properties. In this brief review, the main physical concepts related to the most important physical aspects of turbulence modulation are summarized. Different criteria used to distinguish the enhancement or the attenuation effects of the particles on the carrier phase flows are recalled. For the interest of large-scale industrial applications, several theoretical,experimental and empirical approaches are discussed, which provides an interesting framework for the study of the effect of particles on turbulence behavior modification.

关键词： Particle-induced turbulence Turbulence modulation Physical and numerical modeling

Comparative Study of Three High Order Schemes for LES of Temporally Evolving Mixing Layers

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Communications in Computational Physics 2012年第10期12卷 1603-1622页

作者： Helen C.Yee Bjorn Sjögreen Abdellah hadjadj NASA-Ames Research Center Moffett FieldCA94035USA Lawrence Livermore National Laboratory LivermoreCA94551USA CORIA UMR 6614&INSA de Rouen 76800 St-Etienne du RouvrayFrance

Three high order shock-capturing schemes are compared for large eddy simulations(LES)of temporally evolving mixing layers for different convective Mach numbers ranging from the quasi-incompressible regime to highly compressible supersonic *** considered high order schemes are fifth-order WENO(WENO5),seventh-order WENO(WENO7)and the associated eighth-order central spatial base scheme with the dissipative portion of WENO7 as a nonlinear post-processing filter step(WENO7fi).This high order nonlinear filter method of Yee&Sjogreen is designed for accurate and efficient simulations of shock-free compressible turbulence,turbulence with shocklets and turbulence with strong shocks with minimum tuning of scheme *** LES results by WENO7fi using the same scheme parameter agree well with experimental results compiled by Barone et al.,and published direct numerical simulations(DNS)work of Rogers&Moser and Pantano&Sarkar,whereas results by WENO5 andWENO7 compare poorly with experimental data and DNS computations.

关键词： High order numerical methods numerical methods for turbulencewith shocks DNS LES mixing layer

偏心环空中幂率流体层流流动特性数值模拟研究

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石油钻探技术 2020年第4期48卷 37-42页

作者： Hicham Ferroudji Ahmed hadjadj Titus N Ofei Ahmed Haddad 布米尔达斯布加拉穆罕默德大学碳氢化合物与化学系石油装备可靠性与材料实验室布米尔达斯35000 马来西亚石油科技大学石油工程系斯里依斯干达32610 CRTI工业技术研究中心阿尔及尔16033

Herschel-Bulkley模型(即屈服幂率模型)可用于研究非牛顿流体的流动特性,并能在大范围剪切速率条件下得到准确的预测结果。为此,采用有限体积方法(FVM),研究了内部管柱旋转及流变参数(屈服应力τ0、稠度系数K和流性指数n)对偏心环空(E=0... 详细信息

Herschel-Bulkley模型(即屈服幂率模型)可用于研究非牛顿流体的流动特性,并能在大范围剪切速率条件下得到准确的预测结果。为此,采用有限体积方法(FVM),研究了内部管柱旋转及流变参数(屈服应力τ0、稠度系数K和流性指数n)对偏心环空(E=0.5)中Herschel-Bulkley流体层流区域的轴向、切向速度剖面与压降梯度的影响。研究结果表明,内部管柱转速从100 r/min增加至400 r/min时,会引起最大轴向速度增加,增幅为120%;较低的流性指数(n=0.2)会引起偏心环空宽区域出现二次流;内部管柱转速及流变参数的变化对偏心环空宽区域切向速度剖面有不良影响;内部管柱转速从0增加至400 r/min时,会引起不同偏心环空(E=0.2,0.4,0.6和0.8)内幂率流体压降梯度降低,降低幅度为10%。

关键词：计算流体力学幂率流体偏心环空层流流动流变参数流动特性压降梯度

Effects of Cellulose Fiber Content on Mechanical and Electrical Properties of Polyurethane Based Composites

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材料科学与工程（中英文A版） 2013年第6期3卷 398-406页

作者： Aomar hadjadj Fouad Malek El Miloud Maafi Lan Tighzert Omar Jbara Jean-Luc Dellis Laboratory of Materials Science & Engineering (EA 4695) University of Reims Reims 51687 France Laboratory of Organic Macromolecular Chemistry and Natural Products (URAC 25) Faculty of Sciences Mohamed 1st University Oujda 60000 Morocco Laboratory of Condensed Matter Physics (EA 2081) University of Picardie Jules Vernes Amiens 80039 France

注射对比剂和覆膜支架植入术对CT腹主动脉瘤半自动分割体积测量的可重复性的影响

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国际医学放射学杂志 2014年第5期 495-495页

作者： F.Morin-Roy C.Kauffmann A.Tang S.hadjadj O.Thomas N.Piché 梁雪 Department of Radiology Centre Hospitalier Universitaire de Montréal(CHUM)H?pital Notre-Dame1560 Sherbrooke EstMontréalQuébecCanadaH2L 4M1

摘要目的评估注射对比剂以及覆膜支架植入术对使用分割软件测量腹主动脉瘤的体积与最大直径的可行性、准确性和可重复性的影响。方法 80 例腹主动脉瘤病人的 CT

关键词：腹主动脉瘤可重复性支架植入术覆膜 CT