M. SALMI Mohamed

Optimization of control parameters of a compressible laminar boundary layer
The control by suction of a compressible laminar boundary layer of a stationary, viscous and subsonic flow, around a two-dimensional NACA 0012 profile, has been studied numerically. The physical problem is governed by nonlinear partial differential equations called Prandtl equations. The numerical solution is based on the Cranck-Nicolson scheme, the Thomas algorithm and the Keller method. The results obtained made it possible to determine optimal values for the extent, angle and flow rate of suction. With the optimal values of the suction control parameters, we were able to achieve a laminarity gain that reached 10%.

Microgrid networks represent a crucial model in the field of power transmission and distribution, integrating renewable energy sources with modern control technologies. This research focuses on enhancing the performance of a microgrid system connected to the main grid through a three-phase converter controlled using Voltage Oriented Control (VOC). The microgrid comprises a storage element and a photovoltaic (PV) generation system. To improve system efficiency and power quality, backstepping (BS) controllers are implemented and compared with
traditional control methods. Three control systems are evaluated: a conventional system using Perturb and Observe
(P&O) algorithm for Maximum Power Point Tracking (MPPT) and Proportional-Integral (PI) controllers for grid-side converter (GSC) control, a hybrid system with BS-modified P&O (BSP& O) for MPPT and PI controllers for GSC, and an advanced system employing BS-P&O for MPPT and BS controllers for GSC. The research demonstrates that BS controllers exhibit superior dynamic performance, contributing to improved regulation of DC-link voltage, active and reactive powers. Additionally, they achieve lower Total Harmonic Distortion (THD) values and increase the overall efficiency of the PV system. The proposed advanced control strategy shows particular effectiveness in tracking speed, disturbance rejection, and power quality enhancement. This studyunderscores the potential of nonlinear control techniques in optimizing microgrid operations and facilitating the integration of renewable energy sources into the main grid..

This study presents a method for modelling, predicting, and evaluating the impact of drill materials on the drilling process of hybrid palm/jute polyester composites, with the aim of enhancing hole quality regarding delamination, circularity, and cylindricity. Three drill materials, including High-Speed Steel (HSS), 5 % Cobalt-coated High-Speed Steel (HSS-Co5), and Solid Carbide drills were tested, and their impacts on drilling performance were assessed. Through thorough experimentation and statistical analysis, significant differences in results were observed between HSS drills and both HSS-Co5 and Solid Carbide drills. However, the variation in results between HSS-Co5 and Solid Carbide drill results was minimal. Additionally, the findings highlight notable disparities among drill types concerning uncertainty. The results also indicate that feed rate, drill material, and their interaction play crucial roles in determining drilling efficiency. Specifically, HSS drills consistently outperformed HSS-Co5 and Solid carbide drills, demonstrating superior performance in minimizing delamination, improving circularity, and enhancing cylindricity along with lower uncertainty.

Optimization of control parameters of a compressible laminar boundary layer
The control by suction of a compressible laminar boundary layer of a stationary, viscous and subsonic flow, around a two-dimensional NACA 0012 profile, has been studied numerically. The physical problem is governed by nonlinear partial differential equations called Prandtl equations. The numerical solution is based on the Cranck-Nicolson scheme, the Thomas algorithm and the Keller method. The results obtained made it possible to determine optimal values for the extent, angle and flow rate of suction. With the optimal values of the suction control parameters, we were able to achieve a laminarity gain that reached 10%.

Algeria is considered one of the hottest countries in the world due to the abundance of solar hours,
especially in the south of the country. Therefore, the process of cooling homes and buildings is
considered very important, but it is very expensive for the state. One of the solutions to reduce
unwanted internal heat from buildings is to use solar energy. In this study, we used a solar chimney
connected to a ground pipe to provide ventilation and cooling for a room in a house. Three different
regions of the country were chosen: Algiers, M'Sila and Ouargla. To know the effect of climatic
conditions on air flow in a room with limited dimensions. We simulated the air temperature
distribution inside a room equipped with a solar chimney and connected to a ground pipe using the
Fluent program. Finally, the percentage of energy consumption in the three regions mentioned above
was discussed.

Solar energy is an infinite, unpredictable and permanent energy source among all other energy sources.
Solar energy is a renewable type, clean, and inexhaustible which is sufficiently available on the Algerian territory. This work simulates the feasibility of installing a photovoltaic system insulated with batteries in a school in El Oued, Algeria. where the study is carried out to assess solar radiation and evaluate the technical and economic aspects of the PV system to supply domestic electrical energy needs. The program has been implemented by PVsyst6. The daily electricity consumption is about 42.99 kWh/day. On an annual basis, the energy that is injected into the grid is 19068 kWh. The average performance ratio (PR) of the Si-poly PV system is operated at 62.9% in the simulated study for the planned location.

In this work, an experimental study of the effect of dust on the operation of photovoltaic solar panels was conducted in the Hodna region. For this, a monocrystalline type of solar panel was tested with a power of 100W. A quantity of dust was scattered for the first tests during the month of March 2022, then the voltage and current were measured. The second tests were conducted under outdoor M’sila conditions for two months. The results obtained show that the accumulation of dust on the surface of the panels reduces the passage of solar radiation on the one hand, and leads to a rise in the temperature of the panels on the other hand, which reduces the energy produced by the photovoltaic system. Therefore, periodic cleaning of photovoltaic solar panels is necessary.

This paper's numerical study, which applies the finite volume approach and SIMPLE algorithm, aims to dynamically analyze airflow through a channel with Z-obstacles. Three distinct models were used to place the Z-barriers inside the channel. According to Demartini et al.'s model (2004) and as depicted in exam-ple A from the present analysis, the first Z-barrier (fin) is attached to the top wall (heated) and the second (baffle) to the bottom wall (insulated). The Z-barriers, on the other hand, were positioned in the second model on the same wall (in-line ar-rangement), either on the top surface (two fins in example B) or on the bottom wall (two baffles in example C). With the help of these studies, fluid dynamics in solar air collectors with barriers will be better understood and designed.

The present paper highlights a computational analysis of air-flows around rec-tangular and triangular turbulators inside baffled heat exchanger channels in order to improve heat transfer between the fluid and their heated areas. The dy-namic and thermal fields as well as fluid temperature curves at the outlet of the exchanger are studied. The computational study is conducted by utilizing SIM-PLE algorithm with FLUENT system based on the finite volumes. The analysis clearly demonstrated the presence of highly turbulent flows and the appearance of many vortices in various regions of the exchanger. By comparing the different heat exchangers, it was found that the baffled channel fitted with rectangular tur-bulators produced high fluid temperature values at the channel outlet, indicating the significance of using this rectangular form of turbulators in order to enhance the interaction between the hot spaces and the used fluid.

In this work, an experimental study of the effect of dust and bird droppings on the operation of photovoltaic solar panels was conducted in the Hodna region. For this, two types of solar panels were tested, the first is of monocrystalline type with a power of 100W, and the other is of polycrystalline type with a power of 250W. A quantity of dust was scattered on the first during the months of March and May, then the voltage and current were measured. The second was left under outdoor M’sila conditions for two months. The results obtained show that the accumulation of dust on the surface of the panels reduces the passage of solar radiation on the one hand, and leads to a rise in the temperature of the panels on the other hand, which reduces the energy produced by the photovoltaic system. Therefore, periodic cleaning of photovoltaic solar panels is necessary.

Photovoltaic electricity is obtained by the direct transformation of sunlight into electricity, using photovoltaic system.
The aim of this work is describing the software that we used to estimate the electrical energy produced from solar energy within the university center of M’sila.
An estimated study of the energy supplied by a photovoltaic system, using polysun software was made for the M’sila site.
The estimate of the annual power of the energy supplied is equal to 230 kWh, was produced by the PV Poly 250 module which manufacturer by Anonymous from Vela Solaris company.
The significant increase is observed for the temperatures in the afternoon. The efficiency threshold for the best efficiency is basically 17.2 C° at 14:00 h.

In order to improve the heat exchanges between the absorber and its heat transfer fluid, an air solar collector is produced by undulating the surface of its absorber plate with a certain number of undulations. A numerical simulation, using Gambit and Fluent codes, made it possible to determine and represent the effects of the number of corrugations of the absorber plate on the heat transfer between the absorber plate and the heat transfer fluid, as well as the heat exchange coefficient by convection for different temperature values of this absorber. The results obtained showed that the positive effect of the number of corrugations on the absorber-cooler heat transfer fluid and that it is better for a number of corrugations less than or equal to three. The absorber can be even more efficient if its heat exchange surface is increased or by improving other thermo-physical parameters of its sheet.

The hydrothermal behavior of air inside a solar channel heat exchanged equipped with various shaped ribs is analyzed numerically. The bottom wall of the exchanged is kept adiabatic, while a constant value of the temperature is set at the upper wall. The duct is equipped with a flat rectangular fin on the upper wall and an upstream V-shaped baffle on the lower wall. Furthermore, five hot wall-attached rib shapes are considered: trapezoidal, square, triangular pointing upstream (type I), triangular pointing downstream (type II), and equilateral-triangular (type III) cross sections. Effects of the flow rates are also inspected for various Reynolds numbers in the turbulent regime (1.2 × 104–3.2 × 104). The highest performance (η) value is given for the II-triangular rib case in all Re values, while the square-shaped ribs show a significant decrease in the η along the achieved Re range. The η value at Remax is 2.567 for the II-triangular roughness case. Compared with the other simulated cases, this performance is decreased by about 3.768% in the case of I-triangular ribs, 15.249% in the case of III-triangular ribs, 20.802% in the case of trapezoidal ribs, while 27.541% in the case of square ribs, at the same Remax. Also, a comparison is made with air-heat exchangeds that have non-rough walls and contain cross-shaped VGs presented previously, in order to highlight the effectiveness of the rough surface presence in the baffled and finned channels. The obtained results indicated that the triangular-shaped rib (type II) has the most significant hydrothermal behavior than the other cases. This indicates the necessity of roughness heat transfer surfaces for finned and baffled channels to improve significantly the performance of the air-heat exchangeds they contain.

Global solar radiation is an important parameter in the study of any solar energy project. Global solar radiation measurements are not operational in all cities of Algeria, due to high cost of acquisition, maintenance and technical complexities. To overcome this problem the use of empirical models based on temperature as an interesting and accessible parameter is necessary. In this study, six empirical models namely; Hargreaves and Samani model, Chen model, Li 1 model, Li 2 model, Bristow and Compbell model and Okonkwo model, have been selected from literature to estimate monthly global solar radiation from air temperature data of Djelfa. The city of Djelfa (Algeria) is taken as the sole case of study. The performance of those models was evaluated through several statistical indicators (R², RMSE, MBE, MPE and RPE). The results show the superiority of Li 2 model on the studied models. Based on the evolution of monthly global solar radiation as function of extraterrestrial radiation and air temperature variation, a new model was developed. Comparison between model 4 and the developed one indicates the superiority of the new model. This model has been verified for other Algerian cities such as Biskra and Ghardaia. The data of these regions (global solar radiation, maximum and minimum air temperature) were taken from NASA site web. The results show also the superiority of this new model for these two regions. Therefore, the developed model can be suggested to estimate monthly global solar radiation using only air temperature.

The invention of the transistor in 1948 launched a real technological revolution that continues today there are two families of transistors responding to different operating principles: the bipolar transistors invented in 1984. But they are considered as an old technology. A type of transistors derived the field effect transistors (MOSFET), dominate today and more useful than the bipolar. The current technology needs an intelligence technique, modeling of electronic components by artificial neural network. Our work within this framework, as it presents to us a first step in exploiting the principles fantastic techniques of artificial intelligence in the field of modeling and simulation of electronic components such as MOSFETs.

The aim of this study is the evaluation of a photovoltaic system at different locations in Algeria. We have calculated the system efficiency, the solar energy captured by the system and the electrical energy output. An economic study of a photovoltaic station has been done by estimating the cost of this project operating for a period of 25 years. To achieve this goal, we have selected four regions of the Algerian territory, differing in their climatological parameters: Algiers, Constantine, Oran and Tamanrasset. The measured monthly global solar radiation and temperatures values are taken during six years (2000-2005) from the different meteorological stations. The obtained results have revealed that the calculated electrical power for Tamanrasset was the highest one (358lkWh), the best efficiency was in Constantine (10.3%), however the lowest cost of the project was in Algie4rs and Oran (769.7kDZ).

Global solar radiation is an important parameter
in the study of any solar energy project. Global solar radiation
measurements are not operational in all cities of Algeria, due to
high cost of acquisition, maintenance and technical complexities.
To overcome this problem the use of empirical models based on
temperature as an interesting and accessible parameter is
necessary. In this study, six empirical models namely;
Hargreaves and Samani model, Chen model, Li 1 model, Li 2
model, Bristow and Compbell model and Okonkwo model, have
been selected from literature to estimate monthly global solar
radiation from air temperature data of Djelfa. The city of Djelfa
(Algeria) is taken as the sole case of study. The performance of
those models was evaluated through several statistical indicators
(R², RMSE, MBE, MPE and RPE). The results show the
superiority of Li 2 model on the studied models. Based on the
evolution of monthly global solar radiation as function of
extraterrestrial radiation and air temperature variation, a new
model was developed. Comparison between model 4 and the
developed one indicates the superiority of the new model. This
model has been verified for other Algerian cities such as Biskra
and Ghardaia. The data of these regions (global solar radiation,
maximum and minimum air temperature) were taken from
NASA site web. The results show also the superiority of this new
model for these two regions. Therefore, the developed model can
be suggested to estimate monthly global solar radiation using
only air temperature. the components of your paper [title, text,
heads, etc.] in its style sheet.

Ce document polycopié correspond au support de cours de sources d'énergie.
Le cours vise à donner aux étudiants de physique énergétique un vue générale des différentes sources
d'énergie fossiles et renouvelables.
L'objectif du cours est d'assurer une formation de base large et diversifiée, dans un esprit
multidisciplinaire.
L’étudiant doit avoir des connaissances de bases dans des différentes disciplines telles que : la mécanique,
la mécanique des fluides, thermodynamique, électronique, électrotechnique et la chimie.

L'Algérie s'oriente vers le développement et l'utilisation des énergies renouvelables, et spécialement l'énergie solaire. L'énergie solaire constitue un grand intérêt pour l'électrification rural et la production de l'eau chaude. L'un des avantages réside dans l'intérêt d'une utilisation décentralisée avec absence des couts de transport de l'énergie produite. Ce qui est particulièrement recommandé pour servir les citoyens isolés dans les territoires à faible densité et dont la demande consiste essentiellement à satisfaire les besoins énergétiques de base (lumière, réfrigération, pompage, télévision, radio...). L'installation et la mise en oeuvre des panneaux solaires dépendent fortement des paramètres climatiques influant sur le rendement des cellules solaires. En effet, ces paramètres ne sont pas disponibles et pris en considération dans tout le territoire national, vu le manque de données du au nombre limité des stations météorologiques existant sur le territoire Algérien et la diversité du climat Algérien. Par conséquent, il est nécessaire de savoir et établir des modèles reliant ces paramètres climatiques avec les performances des systèmes photovoltaïques.

Ce document polycopié correspond au support de cours de gisement solaire.Le cours vise à donner aux étudiants de physique énergétique un vue générale sur l’énergie solaire et le mode d'utilisation, en mettant l'accent sur leur processus de production d’électricité et l’eau chaude et les techniques de conversion et les aspects pratiques de leur développement. L'objectif du cours est d'assurer une formation de base large et diversifiée, dans un esprit multidisciplinaire.L’étudiant doit avoir des connaissances de bases dans des différentes disciplines telles que : la mécanique, la mécanique des fluides, thermodynamique, électronique,électrotechnique ; la chimie....etc. ce qui va servir aux étudiants d’élargir leur champs d’intérêts pluridisciplinaires

We present three models for the estimation of hourly global solar radiation for two sites in Algeria, namely: Djelfa (Latitude 34.68°N, Longitude 3.25°E, Altitude 1126 (m)) and Ain Bessem (Latitude 36.31°N, Longitude 3.67°E, Altitude 629 (m)). The models are: the Gaussian distribution model, the model by Collares-Pereira-RabI and the H.A. model (Hourly absolute modelling approach). The experimental assessment was done using recorded values of the hourly global solar radiation on a horizontal plane during the period 2000-2004. The obtained results show a close similarity between the solar radiation values calculated by the three models and the measured values, especially for the first model. The experimental validation shows promising results for the estimation and precise prediction of the hourly global solar radiation.

Le soleil est une source d'énergie renouvelable, inépuisable, propre et suffisamment disponible en Algérie pour des applications rentables.
L’étude sur le potentiel énergétique solaire en Algérie fait apparaître un potentiel considérable pour l’utilisation et l’exploitation de cette forme d’énergie. En effet, l’énergie reçue quotidiennement sur une surface horizontale de 1m2 est de l'ordre de 5 KWh sur la quasi-totalité du territoire national, la durée d'insolation quant à elle dépasse les 2000 heures annuellement et peut atteindre les 3900 heures sur les hauts plateaux et le Sahara.
Une connaissance précise de la distribution de l’irradiation solaire sur un site géographique particulier est d’une importance vitale pour le développement des systèmes photovoltaïques, ainsi qu’à l’évaluation de leurs performances.
L’importance de notre travail repose sur la nécessité de quantifier la distribution de l’irradiation solaire sur le territoire.
Dans ce sens nous avons fait une modélisation du rayonnement solaire de quelques sites algériens (Alger, Ain-Bessam, Constantine, Djelfa, Mascara, Oran et Tamanrasset). Nous avons utilisé les données mesurées du rayonnement solaire et de l'insolation obtenues de l'office national de météorologie (ONM) d'une période de six années (2000-2005), suivi d'une étude estimative d'un projet d'installation des systèmes photovoltaïques par le logiciel RETScreen.
Les résultats trouvés dans notre étude sont :
• Nous avons réalisé un modèle pour estimer la quantité du rayonnement solaire global reçu sur un plan horizontale en Algérie, a partir de l’étude du rayonnement en fonction de l’ensoleillement où on a utilisé l’équation linéaire d’Angström et les modèles sous forme logarithmique et la forme exponentielle.
• Nous avons trouvé une concordance remarquable entre les valeurs estimées par les trois modèles et les valeurs mesurées et surtout dans les sites d’Alger et Oran où on a trouvé que la pente est de l'ordre de 1.
• Les meilleures valeurs de MBE, MAE et RMSE sont (-0.010), (1.312) et (1.640) respectivement pour les différents sites.
• Les performances des systèmes photovoltaïques sont fortement affectées par le rayonnement incident, l'insolation et la température.
• L'estimation de la puissance calculée par le logiciel RETScreen était la plus élevée pour la ville de Tamanrasset qui est égale 3581 KWh.
• Le meilleur rendement du système photovoltaïque obtenu est 10.3% pour la ville de Constantine.
• L’estimation du coût des projets d'installation PV obtenu par le logiciel RETScreen pour les quatre villes : Tamanrasset, Alger, Oran et Constantine est respectivement :
780.2 KDZ, 748.7 KDZ, 769.7 KDZ et 769.7 KDZ.
Les résultats trouvés sont encourageants et nous proposons de faire à l'avenir une étude sur les systèmes photo-thermiques pour une contribution efficace dans le développement de l'énergie solaire de notre pays.

Sputtered amorphous silicon thin films have been grown in an atmosphere of helium-argon gas and the effect of helium dilution investigated. The major observed feature is that helium dilution enhances the deposition rate. The highest deposition rate, six times larger than that obtained under conventional conditions, is reached with equal proportions of helium and argon in the deposition chamber. The influence of helium dilution is explained on the basis of an increase in the argon ionization rate with helium dilution.

Le but de ce travail est l’estimation du flux solaire global mensuel sur la surface d’une région (ici, Mascara en Algérie) en fonction du taux d’ensoleillement en utilisant les mesures de l’irradiation solaire globale sur une durée de trois années (2002-2004). Plusieurs modèles ont été testés. Une variation linéaire du type Angstrom-Prescot, une équation quadratique, une variation logarithmique et une fonction exponentielle ont été utilisées.

Pour tester les différents modèles, une analyse statistique des résultats a été faite. L’erreur quadratique moyenne (RMSE), l’erreur moyenne (MBE) et l’erreur moyenne absolue (MAE), sont les principaux éléments de l’analyse comparative. Les valeurs maximales de MBE, MAE et RMSE sont respectivement 1.683, 4.294 et 6.371. Ceci indique la validité des models utilisés pour évaluer le rayonnement solaire global moyen mensuel.