Harnessing the power of vortices shed in the wake of bluff bodies is indeed a boon to society in the face of fuel crisis. This fact serves as an impetus to develop a device called a hydro vortex power generator (HVPG), comprised of an elastically mounted cylinder that is free to oscillate in the cross-flow (CF) direction even in a low velocity flow field. The oscillatory motions in turn can be converted to useful power. This paper addresses the influence of system characteristics viz. stiffness ratio (k*) and mass ratio (m*) on the maximum response amplitude of the elastically mounted cylinder. Computational fluid dynamics (CFD) simulations have been used here to solve a two way fluid–structure interaction (FSI) problem for predicting the trend of variation of the non-dimensional amplitude Y/D with reduced velocity Ur through a series of simulations. Maximum amplitude motions have been attributed to the lowest value of m* with Ur = 8. However, the maximum lift forces correspond to Ur = 4, providing strong design inputs as well as indicating the best operating conditions. The numerical results have been compared with those of field tests in an irrigation canal and have shown reasonable agreement.

This work brings out the numerical simulation of the stir casting technique for aluminium silicon carbide Metal Matrix Composite (MMC) in a closed crucible and the effect of the blade geometry and rotational velocity on solidification of the metal matrix composite has been predictedusing Computational Fluid Dynamics (CFD) approach. The material used in the crucible is silicon carbide in aluminiummetal matrix. Geometric modelling and meshing have been carried out using ANSYS ICEM CFD. Computer simulations have been carried using the commercial CFD package, ANSYS FLUENT. The calculations used 2-D discrete phase, solidification and melting model and enthalpy method. Mushy state mixing, indicative of the solidification patterns have been studied to predict the most suitable ratio of crucible to blade dimensions and speed of stirring to obtain the most uniform type of solidification which in turn induces some enhanced mechanical properties to the casting.

The hydrodynamic derivatives appearing in the manoeuvring equations of motion are the primary parameters in the prediction of the trajectory of a vessel. Determination of these derivatives poses major challenge in ship manoeuvring related problems. This paper deals with one such problem in which an attempt has been made to numerically simulate the conventional straight line test in a towing tank using computational fluid dynamics (CFD). Free-surface effects have been neglected here. The domain size has been fixed as per ITTC guide lines. The grid size has been fixed after a thorough grid independency analysis and an optimum grid size has been chosen in order to ensure the insensitivity of the flow parameters to grid size and also to have reduced computational effort. The model has been oriented to wider range of drift angles to capture the non-linear effects and subsequently the forces and moments acting on the model in each angle have been estimated. The sway velocity dependent derivatives have been obtained through plots and curve-fits. The effect of finite water depth on the derivatives has also been looked into. The results have been compared with the available experimental and empirical values and the method was found to be promising.

Purpose Stir casting is a promising technique used for the manufacture of Al-SiC metal matrix composites. The clustering of reinforcement particles is a serious concern in this production method. In this work, mushy-state solidification characteristics in stir casting are numerically simulated using computational fluid dynamics techniques to study the clustering of reinforcement particles. Design/methodology/approach Effects of process parameters on the distribution of particles are examined by varying stirrer speed, volume fraction of reinforcement, number of blades on stirrer and diameter ratio (ratio of crucible diameter to stirrer diameter). Further, investigation of characteristics of cooling curves during solidification process is carried out. Volume of fluid method in conjunction with a solidification model is used to simulate the multi-phase fluid flow during the mushy-state solidification. Solidification patterns thus obtained clearly indicate a strong influence of process parameters on the distribution of reinforcement particles and solidification time. Findings From the simulation study, it is observed that increase in stirrer speed from 50 to 150 rad/s promotes faster solidification rate. But, beyond 100 rad/s, stirrer speed limit, clustering of reinforcement particles is observed. The clustering of reinforcement particles is seen when volume fraction of reinforcement is increased beyond 10 per cent. When number of blades on stirrer are increased from three to five, an increase in solidification rate is observed, and an uneven distribution of reinforcement particles are observed for five-blade geometry. It is also seen from the simulation study that a four-blade stirrer gives a better distribution of reinforcement in the molten metal. Decrease in diameter ratio from 2.5 to 1.5 promotes faster solidification rate. Originality/value There is 90 per cent closeness in results for simulation study and the published experimental results.

In this work a ternary Al-Fe-SiC metal matrix composites were reinforced using Zr particles through powder metallurgy process. The Al matrix and the reinforcements were mixed in high energy ball mill at a speed of 250 rpm over a period of 5 h so as to develop a homogenously dispersed composite material. The composite powders are then pressed at 500 MPa using hydraulic press. The compressed composite green compacts are then sintered at 500 °C for 2 h and allowed to cool under furnace atmosphere. The densities, micro hardness and compressive strength of Al-Fe-SiC-Zr composites were investigated and reported. The composite materials were characterized using SEM, EDS and XRD. The density of Al-10Fe-10SiC-10Zr hybrid composites was found to be around 3.44 g cm−3. The Zr particles have influenced the micro hardness of the composite materials. The micro hardness of the Al-10Fe-10SiC-10Zr hybrid composites was found to be better compared to Al-10Fe and Al-10Fe-10SiC hybrid composites. The compressive strength of the Al-10Fe-10SiC-10Zr hybrid composites was around 205 MPa which is 44% higher than the Al-10Fe composite material. The porosity of the hybrid composites has reduced when compared to that of Al-10Fe and Al-10Fe-10SiC hybrid composites. The wear studies reveal that Al-10Fe-10SiC-10Zr bear out better wear resistance. The predominant wear mechanism was identified as adhesive wear followed by plastic deformation. This improved wear resistance was due to the formation of oxides layers such Al2O3, Fe2O3 and also due to the presence of AlFe3 and Al3Zr4 intermetallics.