Journal of Computational Engineering and Physical ModelingJournal of Computational Engineering and Physical Modeling
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Feed provided by Journal of Computational Engineering and Physical Modeling. Click to visit.On the Study of Magnetohydrodynamic Squeezing Flow of Nanofluid between Two Parallel Plates ...
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A study of magnetohydrodynamic squeezing flow of nanofluid between two parallel plates embedded in a porous medium is presented in this work. The ordinary differential equation which is transformed from the developed governing partial differential equations is solved using differential transformation method. The accuracy of the results of the approximate analytical method are established as they agree very well with the results numerical method using fourth-fifth order Runge-Kutta-Fehlberg method. Using the developed analytical solutions, the parametric studies reveal that when the velocity of the flow increases during the squeezing process, the Hartmann and squeezing numbers decrease while during the separation process, the velocity of the fluid increases with increase in Hartmann and squeezing numbers. Also, the velocity of the nanofluids further decreases as the Hartmann number increases when the plates move apart. However, it is revealed that increase in nanotube concentration leads to an increase in the velocity of the flow during the squeezing flow. The present study will be useful in various industrial, biological and engineering applications.Sun, 30 Sep 2018 20:30:00 +0100Wind Pressure Coefficients on Pyramidal Roof of Square Plan Low Rise Double Storey Building
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The present study demonstrates the pressure variation due to wind load on a two storey building with a square plan and a pyramidal roof through CFD simulation. Past cyclone reports and other related post-disaster studies have shown loss of lives and extensive property loss mostly in the cyclone-prone regions of India. Post-disaster studies reveal that a pyramidal roof has much better chances of survival in comparison with other roof shapes. ANSYS Fluent has been used for the simulation and ANSYS CFD-Post has been used for observing the wind pressure on building roofs. The simulations are performed using the realizable k-ε turbulent model by considering grid sensitive analysis and validation with previously published wind tunnel experimental measurements. The present study includes wind behavior around the building model with different roof slopes. Comparisons of pressure coefficients are shown for five wind incidence angles to study the effect of wind on the building. Results indicate that both maximum positive and maximum negative wind pressure coefficients increase with increasing roof slopes. The results of the study are helpful in understanding the damage caused on the roof surface during the extreme wind condition.Tue, 09 Apr 2019 19:30:00 +0100A computational model for estimating the compressive strength of mortars admixed with mineral ...
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In this paper, a new computational model is presented to estimate the compressive strength of mortars admixed with Microsilica and a mineral material namely Wollastonite. For this purpose, an equation with fourteen unknown parameters was considered based on a large experimental data, which were published in the literature. The model used five independent parameters including the amounts of the Microsilica, cement, Wollastonite, water and also the age of the specimens (day). For calculating the unknown parameters, the author used artificial neural network method and divided the experimental database into three parts for three phases of the train, validate and test to tune the coefficients of the considered equation. After determining the coefficients, the final equation was validated and tested to estimate the compressive strength of the considered mortars. The results indicated that the proposed equation of this research could be able to determine the compressive strength of mortars admixed with Wollastonite.Sun, 30 Sep 2018 20:30:00 +0100Comparative Studies of the Effects of Blocking and Water Repellant Agents on Tensile Strengths ...
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The effects of blocking and water repellant coatings applied on fanpalm specimens on the tensile strength were examined. Fanpalm specimens (coated and uncoated specimens) were soaked in sodium hydroxide solution for specific periods up to 1 year to expose item to alkaline attack. Two groups of coating agents (blocking and water repellant agents) were applied as treatment agents. The blocking agents were of three types; sodium sulphate, magnesium sulphate and hydroxylamine, while water repellant agents also were of three types sulphur, bitumen and epoxy. Tensile strength tests were carried out on these specimens and results presented. The result revealed that as the duration of soaking in cement slurry of uncoated fanpalm increases, the nominal ultimate tensile strength of the fanpalm decreases from 107 to 17.50 N/mm2 at 366 days in cement slurry. While the specimens coated with water repellant and blocking agents decreased to 40.67 N/mm2 and 18.33 N/mm2 respectively at 366 days. This shows that coating fanpalm with blocking and water repellants will improved the resistant to chemical attack. up to 270 days. Beyond 270 days the coating specimens with water repellant is more effective. The specimens coated with blocking agents are of lower ultimate strength compared with uncoated specimens within 270 to 366 days in alkaline media.Tue, 09 Apr 2019 19:30:00 +0100ELASTIC BUCKLING OF SINGLE-STEPPED COLUMNS WITH END AND INTERMEDIATE AXIAL LOADS
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Buckling study of single-stepped columns subjected to both intermediate and end axial loads are introduced in this paper. The column understudy is considered as two segments where the upper and the lower parts have different cross-section moment of inertia or different material and subjected to an intermediate load at the location of the cross-section change beside the end load. All the classical end conditions of the studied column are considered in this paper as pinned ends, clamped ends, clamped-free ends and clamped-pinned ends. The analysis is developed using the finite element method to study the effect of the different parameters in the buckling loads. These parameters are i) ratio of the intermediate axial load to the end axial load, ii) the intermediate load location as a ratio to the column span and, iii) the ratio of flexural rigidity of lower segment to that of the upper one. The obtained numerical results are introduced in many interaction curves to obtain the buckling loads for each end conditions considering the other parameters.A comparison between the obtained results and that of the available theoretical studies shows the accuracy and the simplicity of the present work to get the critical load.Sun, 30 Sep 2018 20:30:00 +0100Investigating on hydrodynamic behavior of slotted breakwater walls under sea waves
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Breakwater walls are buildings that are built to prevent the collapse of the soil or other granular materials and the safety of the sea. One of the destructive phenomena in these structures is the impact of sea wave forces on the overturning phenomenon and instability of the coastal wall, which has damaged the structures existing on these sites. The pattern of interaction between water and seas is complex in coastal structures. In this research, the influence of the different wall heights and soil type changes on wall stability and water pressure distribution in the coastal wall have been investigated. Also, studies will be done on the investigation and optimization of the wall and Finally, by comparing the results obtain with classical methods, the strengths and weaknesses of the classical methods have been analyzed and the effectiveness of these methods (classical) has been evaluated.These walls are made in two types of weighted and flexible (mainly metal) types, in which flexible performance is considered in this research. The behavior of metal shields in front of the water will be examined using the ANSYS software. Several methods for calculating wave forces on perforated coastal walls are also reviewed. In this study, the behavior of the elastic wall is assumed. Coastal walls have been investigated in different hardships and the distribution of pressure and anchor due to hydrodynamic pressure of water on the wall have been investigated. The walls are different in terms of material and amount of rigidity.Thu, 18 Apr 2019 19:30:00 +0100Estimation of Aquifer Transmssivity Using Dar Zarrouk Parameters Derived from Resistivity ...
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The shallow alluvial aquifers on the floodplain are the major sources of water supply for the dry season farming activities. The research is aimed to estimate the aquifer transmissivity of the alluvial formations on the floodplain using Dar Zarrouk Parameters derived from geoelectric soundings. Ten profiles of vertical electric soundings (VES) using schlumberger array method with the aid of a sensitive ABEM Signal Averaging System (SAS) was in the investigation. The results revealed five geoelectric layers on the alluvial formation of the floodplain. There were three, four, five, six and seven layers beneath the alluvial formation. The results were compared with the alluvial floodplain lithologies at each sounding points with resistivity values ranging between 0.98 Ωm to 4,113 Ωm and depths varying from 0.01 to 146 m. The geoelectric sequence of the alluvial formations of the flood plain reveals semi aquifer system. The aquifer hydraulic characteristics indicated that the transverse resistance R ranged between 436.8 Ωm2 to 77,324.40 Ωm2 with a mean value of 11,963.71 Ωm2. The longitudinal conductance S ranged between 0.0026 to 1.792 with an average value of 0.26348. The hydraulic conductivity value across the floodplain ranged between 0.16 m/day to 29.79 m/day with a mean value of 5.597 m/day. The transmissivity values obtained for the various layers range between 1.6 m2/day to 834.1 m2/day with an average value of 128.86 m2/day. The results of the hydraulic head reveal that the floodplain recharges the River. High groundwater potential zone occurs in the southern part of the study areaSun, 30 Sep 2018 20:30:00 +0100Numerical investigation of the cooling of shear thinning fluids in cylindrical horizontal ducts
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The present paper is an investigation of the cooling of hot shear thinning fluids flowing through cylindrical pipes. The study is achieved via numerical simulations with the help of the computer code CFX, which is based on the finite volume method to solve the governing equations. The efficiency of two techniques for achieving the cooling process is investigated, namely: the counter flow and the baffling techniques. In the first part and for the first strategy, the hot fluids are cooled by an external turbulent counter flow of a Newtonian liquid. In the second part and in an attempt to enhance the energy efficiency of the heat exchanger system, semi-circular baffles are inserted. We note that two strategies are used in combination in the second part of study. Effects of the flow rates and the pitch ratio of the inserted baffles on the flow and thermal fields are explored. The obtained results show a great enhancement of heat transfer rates when using both strategies in combination.Sun, 30 Sep 2018 20:30:00 +0100Modelling and Simulation of Reinforced Concrete Bridges with varying percentages of Shape ...
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Earthquakes constitute a major problem for mankind resulting in loss of lives and structures. Smart structural materials such as Shape Memory Alloy (SMA) suppress the structural vibration in a structure by adjusting the dynamic performance of the structure. SMA rods are unique for their shape memory effect and super elasticity and have been used as structural reinforcement for earthquake retrofits. This research focused on investigating the appropriate percentage of shape memory alloy and steel reinforcements for the least deflection in the column-capping beam of a 3-span composite Matsurube Bridge in Japan subjected to seismic load. Five different earthquake scenarios were used to obtain the best combination of steel and SMA reinforcement in the columns and capping beam for the best resistance to the earthquake response. Data used for simulations were obtained from the bridge components. It was observed that SMA has a high resistance to seismic loads when combined with steel reinforcement and it is therefore recommended for inclusion in reinforced concrete bridges to serve as means of reducing the effect of earthquakes on structures in earthquake prone areas.Sun, 30 Sep 2018 20:30:00 +0100Seismic Assessment of Steel Moment Frames with Irregularity in Mass and Stiffness
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Irregularity, consider to be one of the main reasons of buildings collapse in recent earthquakes. Irregularity also effects the seismic behavior and maximum capacity of structures. The effect of mass and stiffness irregularity was carried out in this research using static and dynamic analysis. Three frames with 5, 10 and 15 stories with a 20% and 50% increase in mass of the middle stories and a 20% and 50% decrease in the ground level and middle stories were investigated separately. Maximum drift, first mode period, mass participation coefficient, and base shear force were evaluated by using a developed program in MATLAB. The results showed that changes in mass and stiffness causes a maximum increase of shear force by 14% and 5% in short and tall frames respectively. Maximum drift and the longest period in short frame occurred when the stiffness of ground level was decreased by 50 percent. In addition, such irregularity causes around 85% increase in mass participation coefficient in both short and tall frames.Sun, 30 Sep 2018 20:30:00 +0100