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Friction stir welding (FSW) has played a significant role in joining aerospace alloys. During this process, the tool rotational (TRS) speed has been found to significantly affect heat generation compared to other parameters. Therefore, the study has investigated the effect of heat generation on force-torque and mechanical properties at different tool rotational speeds (TRS) in the FSW process through experimentation followed by Artificial Neural Network (ANN) technique. Further, the influence of different TRS ranging between 600 and 1800 rpm with an increment of 400 rpm on considered responses; namely thermal weld cycle, microstructure, and grain distribution in nugget zone (NZ) for 2050-T84 Al-Cu-Li alloy plates, welded using FSW were also investigated. It is observed that the vertically downward force (Z-force), longitudinal force (X-force), and spindle torque (Sp. T) decrease with increasing TRS. It is also observed an increasing (up to 1400 rpm) and then decreasing trend for tensile strength and hardness of welded samples. Moreover, the generation of frictional heat and grain size in NZ is increased with increasing TRS from 600 to 1800 rpm. However, the scanning electron microscope (SEM) micrographs of all-welded samples revealed a ductile mode of tensile fracture. Furthermore, the obtained experimental results were validated using the ANN technique. A quite better agreement has been established among the predicted outcomes from ANN with experimental results.

The effect of different configurations of partial cold walls on laminar natural convection heat transfer for a right-angle triangular cavity heated from below has been studied numerically. The enclosure is filled with water and heat transfer surfaces such as hot and cold walls are maintained at constant temperature. The side and hypotenuse walls of the enclosure are detached from the middle and have been arranged in four different configurations, namely AB, BC, AD and CD for cooling purpose. The finite volume method is used to solve the dimensionless governing mass, momentum and energy equations. The problem has been solved to explore the effects of the pertinent parameters i.e. different configurations of cold walls and variation of Rayleigh number (10 5 ≤ Ra ≤ 10 7 ). Results are obtained from numerical simulation using commercial software package, FLUENT and presented in the form of streamlines and isotherms. The thermal performance of the enclosure has been expressed by local and average Nusselt numbers. From the analysis, it is observed that the temperature distribution and flow field are significantly affected by these parameters. The high heat transfer rate has been observed for the position AB while low for the position CD. Also, the heat transfer rate enhances as the Rayleigh number (Ra) increases.

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This work numerically investigates the natural convection in an arch enclosure filled with Al2O3-water based nanofluid. The left side wall of the enclosure is maintained at a higher temperature than that of right side wall while the remaining walls are kept adiabatic. Two-dimensional steady-state governing equations are solved using the finite volume method (FVM). The present work is conducted to state the effects of pertinent parameters such as nanoparticles volume faction () = 0 to 9%, curvature ratio (CR) = 1 to 1.5 and Rayleigh number (Ra) = 10 4 to 10 6 on fluid flow and temperature distribution. The numerical results are presented in the form of streamlines, isotherms, local and average Nusselt number. It is observed from the investigation that the variables are exhibiting a significant impact on the heat transfer. The heat transfer rate is enhanced with the increment in the volume fraction of the nanoparticles up to 5% and after that it is decreased gradually. The heat transfer rate is increased with the increase of curvature ratio and it is significantly higher at CR = 1.5. As per the expectation, the heat transfer is increased along with the increment in Rayleigh number. A good agreement is found between the present work and experimental & numerical results from the literature.

A numerical work is conducted for the free convection in a right triangular cavity filled with water-based nanofluids. The bottom wall is in a caterpillar wavy shape which is assumed as a hot wall whereas the rest walls of the enclosure are considered as a cold wall. Governing equations of the problem are discretized through the finite volume method. The present study is undertaken to appraise the effect of the constrained parameters i.e. various types of nanofluids (TiO2, CuO, and Al2O3), volume fractions of thenanoparticles and Rayleigh number (Ra=10 5 -10 7 ). The higher augmentation in the rate of heat transfer is observed for the Al2O3-water-based nanofluid for each Rayleigh number.

A numerical investigation through laminar natural convection has been executed to illuminate the effect of curvature ratio in an arch enclosure filled with water. The left side wall of the cavity is maintained at a higher temperature than that of the right side wall while the other walls are kept insulated. The governing equations such as continuity, momentum and energy equation are solved by finite volume method. The effect of pertinent parameters such as curvature ratio (1≤ CR ≤ 1.5) and Rayleigh number (1×10 4 ≤ Ra ≤ 1×10 6 ) and) on heat transfer are calculated by commercial available computational fluid dynamics software, FLUENT 6.3. The fluid flow and heat transfer are shown for fixed Pandtl number 6.5 by streamlines, isotherms and velocity contour. From the investigation, it has been reported that the varying height of the arch cavity and Rayleigh number playing a significant role in heat transfer rate. The variation in heat transfer is calculated in terms of average Nusselt number.