Numerical simulation of laminar flow past a circular cylinder

Rajani, BN; Kandasamy, A.; Majumdar, Sumit K.

doi:10.1016/j.apm.2008.01.017

Cited by 316 publications

(139 citation statements)

References 19 publications

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“…The turbulence is modeled through the kω-SST turbulence model by Menter [43]. Unsteady state computations have been successfully applied to the similar cases in the previous studies of Mahbubar et al [44] and Rajani et al [45]. All the simulations were converged until a satisfactory residual convergence was achieved on the velocities, pressure, and turbulence quantities.…”

Section: Computational Setupmentioning

confidence: 99%

Power Control Optimization of an Underwater Piezoelectric Energy Harvester

et al. 2018

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Abstract:Over the past few years, it has been established that vibration energy harvesters with intentionally designed components can be used for frequency bandwidth enhancement under excitation for sufficiently high vibration amplitudes. Pipelines are often necessary means of transporting important resources such as water, gas, and oil. A self-powered wireless sensor network could be a sustainable alternative for in-pipe monitoring applications. A new control algorithm has been developed and implemented into an underwater energy harvester. Firstly, a computational study of a piezoelectric energy harvester for underwater applications has been studied for using the kinetic energy of water flow at four different Reynolds numbers Re = 3000, 6000, 9000, and 12,000. The device consists of a piezoelectric beam assembled to an oscillating cylinder inside the water of pipes from 2 to 5 inches in diameter. Therefore, unsteady simulations have been performed to study the dynamic forces under different water speeds. Secondly, a new control law strategy based on the computational results has been developed to extract as much energy as possible from the energy harvester. The results show that the harvester can efficiently extract the power from the kinetic energy of the fluid. The maximum power output is 996.25 µW and corresponds to the case with Re = 12,000.

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Section: Computational Setupmentioning

confidence: 99%

Power Control Optimization of an Underwater Piezoelectric Energy Harvester

et al. 2018

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“…The flow remains steady and laminar for Reynolds number between 5 and 47 and the wake starts becoming unstable at a critical Reynolds number around 47, leading to the shedding of alternate vortices from the cylinder surface at definite frequencies, well known as the von Karman vortex street. The laminar vortex shedding is observed to be continuing up to a value of Re of about 190, beyond which the two-dimensional flow becomes unstable which leads to the formation and amplification of three-dimensional instabilities in the far wake region (Zhang et al 1995;Williamson 1996;Thompson et al 1996;Mittal and Balachandra 1997;Mittal 2001;Rajani et al 2009). These three dimensional disturbance leads to the simultaneous formation of spanwise and streamwise vortex structure along the spanwise direction and the far wake zone undergoes transition from laminar to turbulent state.…”

Section: Introductionmentioning

confidence: 99%

LES of Flow past Circular Cylinder at Re = 3900

Rajani

Kandasamy

2016

JAFM

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Transitional flow past a circular cylinder in the lower subcritical regime (Re = 3900) has been analysed using Large Eddy Simulation (LES) coupled to Smagorinsky and dynamic sub grid scale models. These simulations have been carried out using a parallel multiblock structured finite volume code which is based on SIMPLE algorithm. The predictions are validated against detailed measurement data for mean as well as turbulence quantities. The present LES prediction in general agree reasonably well with the measurement data in the near wake region but deviates from the measurement data in the far wake region which may be due to the coarse resolution of the grid in this region. The influence of the SGS model on mean flow quantities as well as on the flow structures are also discussed.

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“…In general, the mean drag force is found to reduce as the Reynolds number augments. The cause is the decline of the viscous contribution which plays a role for the total drag force within the laminar ow regime [51]. The comparison of the amplitudes of uctuating lift coe cient C A L at various Reynolds numbers is displayed in Table 3.…”

Section: Methodsmentioning

confidence: 99%

“…It could be observed that even though the Reynolds number is recalculated, the drag reduction feature of the modi ed cylinder is still satis ed. Another feature which deserves to be mentioned is that in the considered Reynolds number range, the average drag coe cient of ow over usual cylinder changes slightly (which could be referred to the work of Rajani et al [51]). However, the percentage of drag reduction of the modi ed cylinder is signi cant.…”

Section: Drag Forcesmentioning

confidence: 99%

Features of flow past a circular cylinder with a slit

Sheng

Chen

2016

Scientia Iranica

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Abstract. The impact of a slit placed along a circular cylinder diameter, which is parallel to the incoming ow, is numerically investigated in order to nd a geometric modi cation that can help drag reduction, as well as vortex suppression, without any additional energy consumption. The drag reduction is achieved by diverting part of the uid in the front stagnation region into the low pressure zone at the back of cylinder through the slit. The Reynolds number based on the cylinder diameter, D, ranges from 60 to 250. The e ect of the slit width ratio (s=D) on the drag and lift coe cients, the Strouhal number, and the wake ow feature of the cylinder is presented. Favorable reduction of drag and lift coe cients is observed with the rising of slit width ratio. The vortex shedding generated from the slit alters the wake ow thoroughly and drives the vortex shedding derived from the cylinder surface to further downstream.

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Numerical simulation of laminar flow past a circular cylinder

Cited by 316 publications

References 19 publications

Power Control Optimization of an Underwater Piezoelectric Energy Harvester

Power Control Optimization of an Underwater Piezoelectric Energy Harvester

LES of Flow past Circular Cylinder at Re = 3900

Features of flow past a circular cylinder with a slit

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