Journal of the Serbian Society for Computational Mechanics最新文献

{"title":"NUMERICAL INVESTIGATION OF THE NANOFLUID NATURAL CONVECTION FLOW IN A CPU HEAT SINK USING BUONGIORNO TOW-PHASE MODEL","authors":"Yamina Anouar, Abderrahim Mokhefi","doi":"10.24874/jsscm.2022.16.02.02","DOIUrl":"https://doi.org/10.24874/jsscm.2022.16.02.02","url":null,"abstract":"In this paper, a numerical investigation using the finite element method on the cooling capacity of an electronic heat sink has been presented. This heat sink is intended for cooling applications of micro-computer CPUs. It deals with a parallelepipedal block with rectangular fins, filled with a nanofluid and crossed by four cylindrical pipes in which a cooling gas flows and dissipates the heat generated by the processor. Indeed, the cooling occurs by three transfers: the first one evacuates the heat from the processor towards the gas, the second one transfers this heat towards the nanofluid and the last one is cooled from the ambient air by means of the fins laterally arranged on the block. From this work, it has been planned to contribute to the study of the behavior of a nanofluid in the heat sink in the presence of a uniform magnetic field in order to enhance the operating and cooling performances. The effects of some control parameters have been highlighted on the hydrodynamic, thermal, and mass behavior of the nanofluid, namely: the Rayleigh number (103 ≤ Ra ≤ 105), the Hartmann number (0 ≤ Ha ≤ 100), the angle of inclination of the magnetic field (0 ≤ γ ≤ 90°) and the nanoparticles diameter (1 nm ≤ dp ≤ 10 nm). On the other hand, a new fin design has been proposed in this study allowing the enhancement of the heat exchange rate with ambient medium. The studied phenomenon is governed by the equations of the two-phase nanofluid model proposed by Buongiorno and which describe the following balances: mass, momentum, energy and nanoparticles. The system of partial differential equations with initial-boundary conditions has been solved by the finite element method. After performing a mesh independence check and validating with previous papers, the results of the investigation were presented. They showed that the application of a magnetic field significantly reduces the rate of heat exchange. However, increasing the angle of inclination of this field promotes convective heat transfer. Moreover, the use of zigzag fins improves the cooling rate by about 4% for amplitude of 0.05 compared to the standard configuration.","PeriodicalId":42945,"journal":{"name":"Journal of the Serbian Society for Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42296834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"COST-EFFECTIVENESS ANALYSIS OF IN SILICO CLINICAL TRIALS OF VASCULAR STENTS","authors":"Milica Kaplarević, Marija Gačić, G. Karanasiou, D. Fotiadis, Nenad Filipović","doi":"10.24874/jsscm.2022.16.02.08","DOIUrl":"https://doi.org/10.24874/jsscm.2022.16.02.08","url":null,"abstract":"Today, it takes ten to twelve years on average to complete a clinical trial before a new drug is approved and brought to marktet. Moreover, the evaluation of the efficacy and safety of drugs or devices has been performed in the linear and sequential manner with limited change over the past decade. The InSilc project is an EU funded project (www.insilc.eu) within which the InSilc platform was developed for designing, developing and assessing coronary stents. The InSilc platform contains the following modules: Mechanical Modelling Module, 3D Reconstruction and Plaque Characterization Tool, Deployment Module, Fluid Dynamics Module, Drug Delivery Module, Degradation Module, Myocardial Perfusion Module, Virtual Population Physiology and Virtual Population Database. We analyze the cost of three different in silico scenarios for clinical study. In Scenario 1, two different stent designs are compared according to the ISO standard for in silico mechanical tests. Scenario 2 predicts the stenting outcome for a virtual anatomy where design/material could be changed. Scenario 3 compares two stents using the same virtual anatomies from the Virtual vessel database. Cost-effectiveness analysis was performed for real clinical trials with metallic and BVS stent and in silico clinical trials. It was observed that in silico clinical trials are almost 90 times cheaper than real clinical trials for 1000 patients. In Silico clinical trials will not completely replace real clinical studies but the evidence shows that they can significantly reduce the cost of a real clinical study which will open a new avenue for future hybrid real and in silico clinical trials.","PeriodicalId":42945,"journal":{"name":"Journal of the Serbian Society for Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46868099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"FINITE ELEMENT ANALYSIS OF A KNEE JOINT DURING JUMP","authors":"Radivoje Radaković, Aleksandra Vulović, T. Exarchos, Nenad Filipović","doi":"10.24874/jsscm.2022.16.02.06","DOIUrl":"https://doi.org/10.24874/jsscm.2022.16.02.06","url":null,"abstract":"Athletes experience high levels of stress during sports activities. One of the most common activities is jumping. This is a very complex activity, which can lead to injuries and long recovery periods. In this research, professional athletes performed jumps in order to obtain ground force values from a force plate. A combination of ground force measurement and inverse dynamics was used to obtain knee joint force values during jumping. The obtained values were then used for the finite element analysis of a knee joint model in order to calculate stress values in the knee joint, with focus on femoral cartilage and menisci. The highest stress values were obtained at the anterior and posterior horn of the medial meniscus, with the highest stress value of 4.894 MPa. Femoral cartilage had lower value, with the maximum stress of 0.391 MPa.","PeriodicalId":42945,"journal":{"name":"Journal of the Serbian Society for Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49665908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"FREE TRANSVERSE VIBRATIONS OF CANTILEVER BEAM FOR TAPERED THICKNESS PREPARED FROM VARIANT FIBERS REINFORCED POLYESTER","authors":"Nawal H. Al-Raheimy, Lekaa Hammed","doi":"10.24874/jsscm.2022.16.02.01","DOIUrl":"https://doi.org/10.24874/jsscm.2022.16.02.01","url":null,"abstract":"The natural frequency of the cantilever beam for the tapered thickness in the current paper is estimated using a Raleigh-Ritz approach. The study explores the effect of different parameters on the behavior of the beam such as the length of beam “L”, thickness at clamped end “hc”, width “b”, the ratio of thickness at free end to thickness at clamped end “hf/hc”, types of fibers and the concentration of fibers “f” in the resin of unsaturated polyester representing the matrix. The resin can be reinforced by aligned long fibers such as E-fibers glass, Kevlar-49 and carbon fibers. When a tapered beam is formed from a composite material, the natural frequency decreases when the length of the beam and the ratio of the thickness “hf/hc” increase; however, the frequency increases as the width of the beam increases. The thickness at the clamped end likewise increases as the volume fraction of fibers in the resin increases. The carbon fiber beam has a higher natural frequency than the other types of fibers. Finally, the results were compared to other available results and were determined to be consistent.","PeriodicalId":42945,"journal":{"name":"Journal of the Serbian Society for Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47587470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"THE EFFECT OF ROTATION RATES, CYLINDER DIAMETER AND LATERAL BOUNDARIES ON STROUHAL NUMBER IN UNSTEADY REGIMES AT DIFFERENT REYNOLDS NUMBERS","authors":"M. Essahraoui, R. El Bouayadi, A. Saad","doi":"10.24874/jsscm.2022.16.02.04","DOIUrl":"https://doi.org/10.24874/jsscm.2022.16.02.04","url":null,"abstract":"The lateral boundary conditions, rotation rates parameters, domain size, cylinder diameter, and Reynolds number are all responsible for the variation of the Strouhal number. In this study, we have varied the domain size, lateral boundary conditions, downstream locations, and the cylinder diameter at specific values of Reynolds number for stationary and rotating cylinders in order to spot the difference in each case. The effect of the rotating cylinder on the flow behavior downstream leads to a variation of Strouhal number. Thus, we have rotated the circular cylinder clockwise and counter-clockwise in order to visualize its effect on the Strouhal number values. An unsteady study was developed for laminar and turbulent regimes from 𝑅𝑒=60 to 𝑅𝑒=3900.","PeriodicalId":42945,"journal":{"name":"Journal of the Serbian Society for Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47803242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"RENORMALIZATION GROUP METHOD FOR A CLASS OF LAGRANGE MECHANICAL SYSTEMS","authors":"Zheng Mingliang","doi":"10.24874/jsscm.2022.16.02.07","DOIUrl":"https://doi.org/10.24874/jsscm.2022.16.02.07","url":null,"abstract":"Considering the important role of small parameter perturbation term in mechanical systems, the perturbed dynamic differential equations of Lagrange systems are established. The basic idea and method of solving ordinary differential equations by normal renormalization group method are transplanted into a kind of Lagrange mechanical systems, the renormalization group equations of Euler-Lagrange equations are obtained, and the first-order uniformly valid asymptotic approximate solution of Lagrange systems with a single-degree-of-freedom is given. Two examples are used to show the calculation steps of renormalization group method in detail as well as to verify the correctness of the method. The innovative finding of this paper is that for integrable Lagrange systems, its renormalization group equations are also integrable and satisfy the Hamilton system's structure.","PeriodicalId":42945,"journal":{"name":"Journal of the Serbian Society for Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41287396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"UNSTEADY NUMERICAL INVESTIGATION OF FERROFLUID FORCED CONVECTION OVER A DOWNWARD STEP CONTAINING A ROTATING FINNED CYLINDER","authors":"Meriem Toumi, M. Bouzit, Abderrahim Mokhefi, Djamila Derbal","doi":"10.24874/jsscm.2022.16.02.05","DOIUrl":"https://doi.org/10.24874/jsscm.2022.16.02.05","url":null,"abstract":"The unsteady investigation of ferrofluid flow forced convection over a downward step containing a rotating finned cylinder is conducted numerically. The dimensionless partial differential equations of conservation equations for mass, momentum and energy and the boundary conditions associated with them are solved by using the finite element method. Two control parameters are used, the angular velocity Ω (-5, -3, -1, 0, 1, 3, 5) and the Reynolds number Re (10, 20, 50, 100), and their effect as a function of time on flow characteristics and heat transfer is presented. To understand how the rotation of the finned cylinder and Reynolds number affects the heat transfer and fluid flow characteristics, an analysis is made and the results obtained are presented qualitatively by the streamlines and the isotherms and quantitatively by calculating the average and local Nusselt number. It has been observed that the rotation of the finned cylinder enhanced heat transfer significantly. A difference of 177.33% improvement is observed between a rotational speed of a finned cylinder (Ω = -5) in the present paper and that of a cylinder without fin (Ω = 25) in the reference paper.","PeriodicalId":42945,"journal":{"name":"Journal of the Serbian Society for Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43594453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"NUMERICAL INVESTIGATION OF SUPERSONIC FLOW SEPARATION IN THRUST-OPTIMIZED CONTOUR ROCKET NOZZLE","authors":"Bensayah Khaled, Kamri Khadidja","doi":"10.24874/jsscm.2022.16.02.03","DOIUrl":"https://doi.org/10.24874/jsscm.2022.16.02.03","url":null,"abstract":"The difficulties associated with thrust-optimized contour nozzles have led to significant advances in our knowledge of the physical phenomena associated with flow separation. In this study, a fully implicit scheme is implemented using a combined weight function for splitting the flux to analyze the shock patterns in the optimized contour (TOC) that occur during the process of separation, leading to free (FSS) or restricted (RSS) shock separation. The switching FSS/RSS hysteresis at startup and shutdown is also investigated. To better understand and validate the findings and study the properties of the oscillating flow during the start-up procedure, an axisymmetric two-dimensional numerical simulation was performed for the TOC nozzle. A code was developed to solve the unsteady Navier-Stokes equations for compressible nozzle flow with boundary layer/shock wave interactions with the implementation of a full RSM-Omega turbulence model. These findings were used to analyze the separation structures, shock wave interactions, and hysteresis phenomena.","PeriodicalId":42945,"journal":{"name":"Journal of the Serbian Society for Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46498634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"BUCKLING OF SHALLOW SHELLS OF DOUBLE CURVATURE STIFFENED BY RIBS FROM THE OUTSIDE","authors":"A. Semenov","doi":"10.24874/jsscm.2022.16.01.05","DOIUrl":"https://doi.org/10.24874/jsscm.2022.16.01.05","url":null,"abstract":"The results of a computational experiment on the analysis of the effectiveness of placing stiffeners on the outer side of the shell structure are presented. The calculations were carried out on the basis of a geometrically nonlinear mathematical model that takes into account transverse shears and orthotropy of the material. The calculation algorithm is based on the Ritz method and the method of continuing the solution with respect to the best parameter. To take into account stiffeners, the refined discrete method, proposed by the author earlier, is used. Shallow shells of double curvature are analyzed. The structures are made of steel and are simply supported, the stiffening ribs are arranged orthogonally. The values of critical buckling loads are presented. The effectiveness of the location of the stiffeners on the outer side of the shell structure is shown. It is revealed that the location of the ribs on the outside increases the value of the critical buckling load.","PeriodicalId":42945,"journal":{"name":"Journal of the Serbian Society for Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48142612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"THERMAL ANALYSIS OF LAMINAR WATER FLOW OVER A BACKWARD FACING CHANNEL WITH CARBON NANOPARTICLES","authors":"S. Saha, V. Ramachandra Prasad, Osman Anwar Bég","doi":"10.24874/jsscm.2022.16.01.09","DOIUrl":"https://doi.org/10.24874/jsscm.2022.16.01.09","url":null,"abstract":"In the last few years, the thermo-hydraulic simulation of nanofluid flow bifurcation phenomena has become of great interest to researchers and a useful tool in many engineering applications. FVM has been employed in this article to numerically explore the laminar water flow over a backward facing channel with or without carbon nanoparticles (CN). The problem formulated in this paper has been solved by considering the effects of nanoparticle weight percentages (𝑤%), such as 0.00, 0.12, and 0.25 for different Reynolds number (𝑅𝑒). Nusselt number distribution (𝑁𝑢(𝑥)), coefficient of skin friction (𝐶𝑓), characteristics of pressure drop (Δ𝑝), velocity contours, static temperature, pumping power (𝑃𝑝) and thermal resistance factor (𝑅) have been investigated to know the behavior of thermo-hydraulic flow bifurcation phenomena. The present study shows that the surface temperature and coefficient of heat transfer can be reduced due to the effect of 𝑅𝑒 or w%. For different w%, it has been found that in the rise in the values of 𝑅𝑒 causes the increase of vortex length and as a result velocity gradient and Δ𝑝 arises. Furthermore, it has also been studied that the enhancement of 𝑅𝑒 causes the increaseof 𝑃𝑝 and Δ𝑝.","PeriodicalId":42945,"journal":{"name":"Journal of the Serbian Society for Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41639555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}