Hicham Rouijaa - Academia.edu (original) (raw)

Papers by Hicham Rouijaa

Fluid Dynamics & Materials Processing

The effect of the tilt angle on mixed convection and related heat transfer in a "T" shaped double... more The effect of the tilt angle on mixed convection and related heat transfer in a "T" shaped double enclosure with four heated obstacles on the bottom surface is numerically investigated. The considered obstacles are constantly kept at a relatively high (fixed) temperature, while the cavity's upper wall is cooled. The finite volume approach is used to solve the mass, momentum, and energy equations with the SIMPLEC algorithm being exploited to deal with the pressure-velocity coupling. Emphasis is put on the influence of the tilt angle on the solution symmetry, flow structure, and heat exchange through the walls. The following parameters and related ranges are considered: Rayleigh number 10 4 ≤ Ra ≤ 5.10 5 , tilt angle 0°≤ φ ≤ 90°, Reynolds number 100 ≤ Re ≤ 1000, Prandtl number Pr = 0.72, block height B = 0.5, opening width C = 0.15, and distance between blocks D = 0.5. The results reveal different branches of solutions on varying Re and φ. They also show that the symmetry of the solution regarding the P 2 axis is retained for all cases with no tilt and for values of Re between 100 and 1000. KEYWORDS Mixed convection; heat transfer; inclination angle; "T" shaped double cavity Nomenclature A Aspect ratio of calculation domain (A = L′/H′ = 2) B Dimensionless block height (B = h′/H′ = 0.5) C Dimensionless openings diameter (C = l′/H′ = 0.15) D Dimensionless space between blocks (D = d′/H′ = 0.5) d′ Space between adjacent blocks (m) f v Action of external volume forces ðf v ¼ qgÞ p Dimensional pressure P Dimensionless fluid pressure (P m /(ρU 0 2)) This work is licensed under a Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

ITM Web of Conferences

The primary objective of this paper is to model transmission lines with frequency-dependent param... more The primary objective of this paper is to model transmission lines with frequency-dependent parameters loaded with linear and nonlinear terminations using an approach based on Pade approximations. To validate our algorithm in the case of lines with constant losses and frequency-dependent parameters, examples of applications in the time and frequency domains are presented. The simulations and obtained results are reported and analysed.

International Journal of Microwave and Wireless Technologies

This paper presents an analysis of the radiated susceptibility of multiconductor shielded cables ... more This paper presents an analysis of the radiated susceptibility of multiconductor shielded cables within complex structures following a hybrid method using moments (MoM) circuit models. The MoM code was used to compute the currents on the shielding induced by an external electromagnetic field and incorporated into a circuit model. The proposed method can be employed for nonlinear loads. The method was tested on two cases: coaxial shielded cables inside a cavity and a car with complex wiring, including a coaxial cable, a twinax cable (a cable with two parallel wires), and a triaxial cable (a cable with three parallel wires), all of which are excited by an incident plane wave. The proposed method provides high accuracy and significant speed gain, and its results are in good agreement with those obtained in other studies.

2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring)

This paper is devoted to the modeling of transmission lines in the frequency and time domain. A M... more This paper is devoted to the modeling of transmission lines in the frequency and time domain. A Multiconductor Transmission Lines (MTL) modeling approach based on Pade approximations is proposed. The main objective is to model the transmission lines with or without shielding taking into account the variable losses characterized by linear parameters dependent on the frequency. In addition, this approach is compared to the other two modeling methods namely the traditional cascade model and Branin model. In a first step, we determine the relative admittance matrix for the line as a function of the linear parameters and the Pade polynomials. This matrix is associated with a macro-model called Pade. This macro-model is then implemented in the Emcap2000-Esacap circuit simulator using the Modified Nodal Analysis method (MNA). In order to validate our algorithm in the case of lines with constant losses, examples of applications in the time and frequency domain are presented. The first example presents a single transmission line that will be analyzed in the time and frequency domain by three different approaches namely the cascade model, Branin model and the pade approximation method. The second example deals with a multi-wire line of two conductors and the third example presents a line of three coupled conductors that will be analyzed by the Branin and the Pade approximation methods. The performed simulations and obtained results are reported and analyzed.

We study the effect of inclination angle on mixed convection in a “T” form cavity containing two ... more We study the effect of inclination angle on mixed convection in a “T” form cavity containing two openings and two heated blocks mounted on its lower wall. The blocks are maintained at a constant temperature TH . The lower wall is adiabatic and submitted to a vertical air jet while the upper wall is kept cold at a constant temperature TC<TH . The vertical walls are rigid and adiabatic. The governing equations are solved by a finite volume method. Special attention is devoted to the solution symmetry, the flow structure and the heat exchange through the cavity. The considered control parameters are: the inclination angle 0◦ ≤ φ ≤ 90◦, the Rayleigh number 105 ≤ Ra≤ 106, the Reynolds number 100≤ Re≤ 1000, the Prandtl number Pr=0.72, the height of the blocks B=0.5, the opening width C=0.15 and the distance between blocks D=0.5. The results are presented in terms of streamlines, isothermal lines and variations of Nusselt number with Re or φ .

sein d’une cavité carrée avec chauffage et refroidissement variables Sliman MANAR, Hicham Rouijaa... more sein d’une cavité carrée avec chauffage et refroidissement variables Sliman MANAR, Hicham Rouijaa, El Alami Semma Mustapha El Alami, 1 Laboratoire de Mécanique, Faculté des Sciences et Techniques, Université Hassan Ier Université Cadi Ayyad, Faculté Polydisciplinaire de Safi BP4162, Route Sidi Bouzid, Safi, Maroc. Groupe de Thermique, Département de Physique, Faculté des Sciences, Université Hassan II Aïn Chock, BP. 5366 Maarif, Casablanca, Maroc; hrouijaa@hotmail.com

International Journal of Innovation and Applied Studies, 2019

The overall objective of this research work is to map Lean initiatives in Moroccan companies, to ... more The overall objective of this research work is to map Lean initiatives in Moroccan companies, to understand the implementations in terms of Lean tools and continuous improvement project and also to identify the adaptations and adjustments necessary to the application of the Lean approach taking into account local specificities related to culture, history, geographical location and technical and organizational aspects. In this context, we will present a state of the art on previous research that has addressed the issues of productivity, hunting waste and implementation of continuous improvement approach and operational excellence in Moroccan companies. We will then focus on the problem of the maturity of Lean management and the self-assessment tools of the Lean maturity that we intend to develop and adapt for Moroccan companies and especially SMEs.

International Journal of Innovative Technology and Exploring Engineering, 2020

The overall objective of this research study is to map the Lean initiatives in Moroccan companies... more The overall objective of this research study is to map the Lean initiatives in Moroccan companies. Understanding in place in terms of Lean tools and continuous improvement project. Identify adaptations and adjustments necessary for the implementation of the Lean approach taking into account local specificities relating to culture, history, geography and the technical and organizational aspects. In this context, we present a state of the art on earlier research dealt with productivity issues, from war on waste and implementation process of continuous improvement and operational excellence in Moroccan companies.

$Research paper thumbnail of Study of Parameter Influence on Quality on the Electromagnetic Imaging Reconstruction from the Spectrum of the Diffracted Field: Application to Reconstruction of the leakage Current of ISM Applicators$

Advanced Electromagnetics, 2019

The ISM applicators generate leakage currents that can disrupt satellite TV transmission, taking ... more The ISM applicators generate leakage currents that can disrupt satellite TV transmission, taking into account the effects of the electromagnetic waves and those of the CEM. We are interested in these as a way to reconstitute their leakage currents, using the Micro-waves Imagery. We propose such a method of spectral analysis, which is intended to reconstruct the equivalent current distribution (position and form) to an object starting from the diffracted field spectrum by the Micro-waves Imagery. Our contribution resides in the influence of different parameters (N number of the measurement point, and the distance z0 of the measurement plane) on the reconstitution quality. This method is presented and illustrated; an algorithm of reconstructing the image of an object existing within a surrounding homogenous medium with known dielectric properties, this algorithm is developed with MATLAB. This method leads to more significant results, and quickly permits to get information about the ob...

Analele Universitatii "Ovidius" Constanta - Seria Matematica, 2017

In this paper we develop a new β-method applied to the resolution of homogeneous transmission lin... more In this paper we develop a new β-method applied to the resolution of homogeneous transmission lines. A comparison with conventional methods used for this type of problems like FDTD method or classical β-method is also given. Furthermore, various numerical experiments are presented to confirm the accuracy, efficiency and stability of our proposed method. In particular, these simulations show that our new scheme is unconditionally stable and fourth-order accurate in space and time.

International Journal of Microwave and Wireless Technologies, 2017

This paper studies the variation effects of incident plane wave on shielded coaxial cables, using... more This paper studies the variation effects of incident plane wave on shielded coaxial cables, using Branin's method, which is called the method of characteristics. That model can be directly used for the time- and frequency-domain analyses. Moreover, it had the advantage of being used without the need of setting the preconditions of the charges applied to its ends. This makes it easy to insert in circuit simulators, such as SPICE, SABER, and ESACAP. The results obtained under ESACAP were remarkably similar to other results, which reinforce the validity of the model. Finally, we will discuss the effects of the variation of the incident plane wave.

Http Www Theses Fr, 2004

L'objet de ce travail est la modelisation des lignes de transmission multifilaires dans le do... more L'objet de ce travail est la modelisation des lignes de transmission multifilaires dans le domaine temporel. Nous rappelons dans un premier temps les differentes methodes permettant le calcul des courants et des tensions distribuees sur la ligne de transmission uniforme comportant N conducteurs. Ces methodes sont souvent limitees pour des lignes a pertes constantes ou faibles, et pour des charges lineaires. D'autre part, elles ont toutefois pour inconvenient majeur d'accroitre la duree des calculs d'un facteur directement proportionnel au rapport liant la dimension des lignes a la longueur d'onde. Contrairement a la methode en cellules cascades, la methode proposee, base sur l'approximants de Pade, permet de reduire le nombre de cellules, et par consequent la duree du calcul. Par ailleurs, elle permet de tenir compte des pertes dependantes de la frequence. Cette methode est representee par un modele circuit, facile a implementer dans les simulateurs circuits, comme Esacap, Spice et Saber. Afin de s'assurer de la stabilite des resultats donnes par ce modele, une etude a ete effectuee a partir de la matrice admittance en utilisant le critere de passivite. Ce modele est ensuite etendu aux lignes blindees en tenant compte de l'impedance de transfert du blindage. Des exemples d'applications, de simulations issues de la litterature ont ete presentes pour valider ce modele.

... 5366 Maarif, Morocco; m.elalami@fsac.ac.ma ; elalami_m@hotmail.com 3 Technical Faculty of des... more ... 5366 Maarif, Morocco; m.elalami@fsac.ac.ma ; elalami_m@hotmail.com 3 Technical Faculty of des Sciences, Hassan 1th University, BP. 577 Settat, Morocco. Corresponding author: semmaalam@yahoo.fr Page 2. ... 2007] or horizontal channels [Najam et al. ...

This paper presents a study of modeling and simulation of the lossless and lossy multiconductor t... more This paper presents a study of modeling and simulation of the lossless and lossy multiconductor transmission lines in frequency domain. This study is based on a characteristics method, which permits modeling the line as a quadripole whose advantage is not to presuppose applied charge conditions in its extreme. This permits it to be introduced easily in the circuit simulators such as Spice, Esacap and Saber. The results presented here cover two types of multiconductor transmission lines, the "Ribbon Cable" and "2Wire Xtalck.

International Journal of Microwave and Wireless Technologies, 2015

This paper addresses the study of the variation effects of incident plane wave on a multiconducto... more This paper addresses the study of the variation effects of incident plane wave on a multiconductor transmission line (MTL), using a coupling circuit model of MTL line with plane wave based on the method of characteristics (Branin method). This model is valid in the time and frequency domains. It has also an advantage of not presupposing the conditions of the charges applied to its ends, which allows it to be easily inserted in circuit simulators, such as SPICE, SABER, and ESACAP. We confirm the validity of this model by comparing our simulation results under ESACAP with other results, and we discuss the variation effects of the incident plane wave on an MTL line.

Proceedings of 2014 Mediterranean Microwave Symposium (MMS2014), 2014

The resolution of the telegrapher's equations allow to determine the voltage and current magn... more The resolution of the telegrapher's equations allow to determine the voltage and current magnitudes at any point on the line provided that the per-unit-length parameters of the components of the connections are rigorously determined. In this context, various formulations and methods have been developed to determine the per-unit-length parameters. In this paper, we are particularly interested in the resolution of the linear parameters of a multiconductor transmission line (MTL) with two numerical methods based on the method of moments.

International Journal of Microwave and Wireless Technologies, 2014

This paper presents an optimization circuit model of multiconductor transmission lines in the tim... more This paper presents an optimization circuit model of multiconductor transmission lines in the time domain. Several methods allow calculation of the currents and the tensions distributed on the uniform transmission line. Most of these methods are limited to lines with constant losses, and only for linear loads. The macro-model we propose, using Pade approximant, employs more variables and allows it to reduce the necessary cells' number in modelization than the traditional cells cascade method. This macro-model, using the Modified Nodal Analysis method (MNA), is suitable for an inclusion in circuit simulator, such as Esacap, Spice, and Saber. The MNA method offers an efficient means to discretize transmission lines on real and complex cells compared to the conventional lumped discretization. In addition, the model can directly handle frequency-dependent line parameters in the time domain. An example, with experimental measures taken from literature, is presented to validate the mo...

2009 International Conference on Microelectronics - ICM, 2009

... its extreme. This permits it to be introduced easily in the circuit simulators as Spice, Esac... more ... its extreme. This permits it to be introduced easily in the circuit simulators as Spice, Esacap and Saber. Diverse examples ... its extremes. This permits it to be introduced easily in circuit simulators as Spice, Esacap and Saber. Diverse examples ...