This study numerically investigates laminar flow around two prismatic bodies, specifically square cylinders, arranged in tandem. The analysis covered gap ratios ($L/D=2$–7) and Reynolds numbers ($Re$ = 100–200), focusing on quantifying the aerodynamic characteristics and examining the wake flow structures within the established interference regimes. The time-averaged and unsteady parameters, including the drag and lift coefficients, RMS lift, vortex formation length, Strouhal number, recirculation length, wake width, and pressure distribution, were evaluated for both cylinders. A consistent critical spacing of $L/D\approx 4.5$ was observed across all Reynolds numbers, coinciding with the minimum Strouhal number, a sharp increase in unsteady lift, and divergence in wake width between cylinders. Notably, in the range $4.5\lesssim L/D\lesssim 6.5$ at higher $Re$, the DC exhibited a mean drag exceeding that of an isolated cylinder, attributed to base-pressure reduction and accelerated inflow from the upstream wake. A critical spacing in the co-shedding regime produced strong drag amplification on the DC, attaining an overall maximum value of 50.41% at $Re=200$ and $L/D=6.0$. To note, unlike mean drag, mean lift is found to be zero in all interference cases for both cylinders, irrespective of spacing ratio and Re, owing to the symmetry of the time-averaged pressure distribution on either side of the cylinders. Spectral and phase analyses reveal a transition from broadband, desynchronised oscillations to a frequency-locked state, with the phase angle between the cylinders reducing sharply to $\Delta \varphi \approx 0^{\circ }$ at the critical spacing. This indicates complete in-phase synchronisation or symmetry of the vortex-shedding process between the cylinders at the critical spacing. This confirmed the hydrodynamic transition between the coupled and independent shedding modes of the cylinders. The recirculation lengths for the DC reduce to as low as $0.6D$ in the co-shedding regime, highlighting rapid wake recovery. The research presented here offers new insights into force modulation, the evolution of wake structures, and the sensitivity to the Re that occurs when laminar flow occurs between two tandem square cylinders. These findings can be utilised to develop methods for controlling VIV and designing thermal-fluid systems.

Numerical simulation results on the effect of corner arc (radius `r') on the aerodynamic characteristics of a square section cylinder (side dimension, B) are presented in this paper. Simulation was carried out by using the commercial code ANSYS-Fluent at a Reynolds value of 2100 (based on B). Results show that as r/B ratio (CR) increases, coefficients of drag and lift decrease till CR = 0.2 further to which they increase. Whereas, Strouhal number registers an opposite trend as that of drag and lift. It is inferred that the value of the percentage of drag reduction is around 21.49% for corner ratio 0.2 configuration, which also has the highest Strouhal number = 0.17 and it proves to be the most effective configuration out of all the configurations attempted in this study.

Turbine blade tips are subject to burn out owing to leakage flow. Tip clearance flow arises due to the flow of unexpanded hot combustion gas through the interstice between turbine rotor blade tip and fixed shroud. In the present study we are numerically analyzing the effect of 4 tip modifications like dimpled tip (DIM), double squealer tip (DSS), pressure side squealer tip (PSS), and suction side squealer tip (SSS) on a plain tip. The influence of tip modifications on the effectiveness of turbine was estimated using parameters such as total pressure loss coefficient and vorticity magnitude and loss estimation using correlations. The study was conducted for various tip clearances such as 0%, 1.5%, 2.3% and 5% with respect to the blade span. Linear turbine cascade with 5 blades were used for this study. Simulations are carried out using commercial CFD solver, ANSYS FLUENT 14.0. Standard cascade loss estimation correlation was used. In the midst of tip shapes tested, double squealer tip and dimpled tip seemed to have the pre-eminent total pressure loss coefficient diminution. Both tip modifications significantly reduces the clearance leakage through the space between tip and casing, which consecutively depreciate the secondary losses adjacent to the convex surface of the blade. Correlation for losses through cascade showed a linear relationship between tip clearance loss and tip clearance gap. These tip modifications can be used in any kind of turbo machines for better performance with improved efficiency.

In present day shell and tube heat exchanger is the most common type heat exchanger widely used in industries, because it suites high pressure applications. The process involving stimulation consists of modeling existing and newly designed geometry and meshing the new geometry of shell and tube heat exchanger using CFD package 14.0.The objective of the project is to modify the existing heat exchanger in order to reduce the preheating time. We focus on numerical comparison of the existing design with the newly constructed geometry. Analytical data obtained for the new design is compared with the existing one. The actual design consisting of 49 U Tubes with 10mm diameter, length 1225mm and shell diameter 168mm is converted in to 18 tubes with 25.4m diameter, length 2050mm and shell diameter 273.1mm.