The main objective of this research is to improve the design and performance of the polyurethane foam-filled thin-walled aluminum Grooved circular tubes using multi-response optimization (MRO) technique. The tubes are shaped with the inner and the outer circular grooves at different positions along the axis. For this aim, several numerical simulations using ABAQUS finite element explicit code are performed to study the energy absorption of these structures. The effects of the grooves distance, tube diameter, grooves depth, foam density, and tube thickness are investigated on the crash worthiness parameters of Grooved circular tubes. Finite-element analysis is performed along the lines defined by design of experiments (DOE) technique at different combinations of the design parameters. The MRO is carried out using the mathematical models obtained from response surface methodology (RSM) for two crashworthiness parameters termed as the specific energy absorption (SEA) and the crushing force efficiency (CFE). Finally, by analyzing all the design criteria including the absorbed energy of tube, the mass of tube, the mean crushing load, and the maximum crushing load, the optimal density of polyurethane foam and geometric parameters were obtained through both multi-objective optimization process and Pareto diagram. A comparison of the obtained results indicates the significance of grooves distance and the inner diameter of the tube as the most influential parameters.

This study experimentally evaluated the mixing augmentation of twin tabs mounted along a diameter at the outlet of a convergent-divergent Mach 1.62 circular nozzle. The usefulness of the plain and Grooved tabs is examined at various expansion levels prevailing at nozzle outlet. The tab's performance is assessed through pitot pressure distribution measured along and perpendicular to the jet centerline at different nozzle pressure ratios (NPRs). The shadowgraph technique visualized the shocks and expansion fans in uncontrolled and controlled jets. With the introduction of uncorrugated or plain tabs at the nozzle outlet operating under overexpanded conditions corresponding to NPR 4, the supersonic length (SL) was decreased only by 35.4%. On the other hand, the corrugated or Grooved tabs under similar conditions decreased the SL substantially. Interestingly, the performance of Grooved tabs was best at underexpanded conditions associated with NPR 6, where the SL was reduced by about 88%. The pressure profiles also established the superiority of tabs with Grooved edges in mixing augmentation without introducing any significant asymmetry to the flow field. In addition, the Shadowgraph images also confirmed the weakening of shock strength and reduction of shock-cell length in the case of Grooved tabs at the nozzle exit compared to the plain nozzle.

In this paper, buckling of cylindrical Grooved shells under axial load has been examined by theoretical and experimental methods. The shell is made of USA/API – X42 5L steel standards. This material is one of the most common materials used in gas, oil and petrochemical industries. The effect of spiral grooves on cylindrical shell was analyzed, and the results obtained from the Abaqus software were compared with experimental results. Theoretical and experimental results were in good agreement. Hence, the numerical results can be used as well. It was also found that the number of grooves on the critical buckling load has an important role so that the critical buckling load decreases with an increase in critical load groove.

In this study, the flow field of a new secondary-Grooved cylinder is determined by using particle image velocimetry (PIV) to understand the wake characteristics at different depths of the secondary Grooved cylinders. In order to analyze the wake characteristic behind the secondary Grooved cylinder with different depths, time-averaged streamlines, time-averaged velocity, RMS velocity, Reynolds stress, turbulent kinetic energy, and instantaneous flow structures are employed. The recirculation zone for secondary Grooved cylinders with different depths decreases when compared to the smooth cylinder, the peak magnitudes of flow velocity fluctuation intensity and transverse velocity fluctuation intensity for secondary Grooved cylinders with different depths are reduced and the locations appear delayed. Furthermore, in contrast to the smooth cylinder, the secondary Grooved cylinders with different depths' Reynolds stress and turbulent kinetic energy are increased by the wake flow, and the transient large-scale vortex is split into several smaller-scale vortices behind the secondary Grooved cylinders. The results obtained for the above flow structure are more significant when h/D = 0. 05 for the secondary Grooved cylinder.

In the present study, mixed convective heat transfer inside a square enclosure in the presence of a rotating cylinder with various numbers of grooves is presented. Effects of counterclockwise and clockwise rotations with non-dimensional rotating speeds (RS) in the range from -1000 to 1000 are studied for different radius ratios (R) of 0.1, 0.2, and 0.3. Computations are carried out for Rayleigh numbers 103, 104, and 105 using the finite volume approach. The obtained results are validated against the available data for an empty enclosure (in the absence of a cylinder) as the reference case and also for an enclosure with a rotating smooth cylinder. It is demonstrated that for a specific value of the Rayleigh number, increasing the radius ratio enhances the thermal performance inside the enclosure regardless of the groove number and rotating speed. Increasing the Rayleigh number attenuates the roles of rotating speed and radius ratio, gradually. It is concluded that among all cases, the case with counterclockwise rotating smooth cylinder and among the Grooved cases, Case 5 with three grooves provide the maximum heat transfer enhancements.