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Vagesh D. Narasimhamurthy

Bio: Vagesh D. Narasimhamurthy is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Reynolds number & Turbulence. The author has an hindex of 11, co-authored 46 publications receiving 455 citations. Previous affiliations of Vagesh D. Narasimhamurthy include Norwegian University of Science and Technology.


Papers
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Journal ArticleDOI
TL;DR: In this paper, the three-dimensional wake flow behind a flat plate placed normal to the free stream has been investigated by means of direct numerical simulations and the Reynolds number Re based on the homogeneous inflow velocity and the uniform width d of the plate was 750.

81 citations

Journal ArticleDOI
TL;DR: In this article, the authors present a simulation of a pipeline release scenario, in which dense-phase CO2 is released from a full-bore 36-in. pipeline, and the resulting multiphase CO2 plume disperses over complex terrain, featuring hills and valleys.

43 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigated the properties of asymmetric wake patterns behind a flat plate inclined at angles of attack 20°, 25°, and 30° by direct numerical simulations.
Abstract: The properties of asymmetric wake patterns behind a flat plate inclined at angles of attack 20°, 25°, and 30° are investigated. The Reynolds number based on the inflow velocity and the plate width is 1000. Both two-dimensional and three-dimensional calculations are performed by direct numerical simulations. Compared to the three-dimensional simulations, the two-dimensional calculations predict a significantly lower pressure on the rear surface of the plate, which consequently leads to very high drag and lift forces on the plate. The asymmetric mean wake flow, turbulence properties, and coherent patterns in the three-dimensional simulations are analysed by time- and phase-averaged techniques. Unlike the symmetric wake flow, the vortices shed from the leading and trailing edges of an inclined plate possess unequal strength with the trailing edge vortex having higher strength. It is observed that the present three-dimensional simulations predict results which compare well with the experimental data. In addit...

39 citations

Journal ArticleDOI
TL;DR: In this paper, a tapered circular cylinder with taper ratio 75 placed normal to the inflow has been studied and it was observed that even with a very long time sampling a discrete cellular shedding pattern prevails.
Abstract: Vortex shedding behind a tapered circular cylinder with taper ratio 75 placed normal to the inflow has been studied. The Reynolds numbers based on the uniform inflow velocity and the diameter of the cylinder at the wide and narrow ends were 300 and 102, respectively. In the present direct numerical simulation study it was observed that even with a very long time sampling a discrete cellular shedding pattern prevails. This is in contrast to what Parnaudeau et al. [J. Turbulence 8, 13 (2007)] speculated in their tapered cylinder study, where they suggested that with a longer time sampling a diffused cellular pattern might appear. In the present investigation it was found that streamwise vorticity increases as vortex dislocation occurs, an effect also reported by Piccirillo and Van Atta [J. Fluid Mech. 246, 163 (1993)] in their experimental study. Flow visualizations revealed that both modes A and B secondary flow structures coexist along the span of the present tapered cylinder. The wavelength of mode B is ...

36 citations

Journal ArticleDOI
TL;DR: Assessment of three well-known RANS eddy viscosity models, namely, Standard k-e, Re-Normalization group (RNG) k-E and Realizable k- e, in a representative range of gas dispersion cases by comparing models’ behavior with experimental data shows promise in yielding good results in cases involving complex-geometries and dense-phase gas-releases.

35 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, the authors review the current state-of-the-art of CO2 capture, transport, utilisation and storage from a multi-scale perspective, moving from the global to molecular scales.
Abstract: Carbon capture and storage (CCS) is broadly recognised as having the potential to play a key role in meeting climate change targets, delivering low carbon heat and power, decarbonising industry and, more recently, its ability to facilitate the net removal of CO2 from the atmosphere. However, despite this broad consensus and its technical maturity, CCS has not yet been deployed on a scale commensurate with the ambitions articulated a decade ago. Thus, in this paper we review the current state-of-the-art of CO2 capture, transport, utilisation and storage from a multi-scale perspective, moving from the global to molecular scales. In light of the COP21 commitments to limit warming to less than 2 °C, we extend the remit of this study to include the key negative emissions technologies (NETs) of bioenergy with CCS (BECCS), and direct air capture (DAC). Cognisant of the non-technical barriers to deploying CCS, we reflect on recent experience from the UK's CCS commercialisation programme and consider the commercial and political barriers to the large-scale deployment of CCS. In all areas, we focus on identifying and clearly articulating the key research challenges that could usefully be addressed in the coming decade.

2,088 citations

Journal ArticleDOI
TL;DR: In this article, a review of the data and models for CO 2 transport is presented, including transient flow data and model for pipes, including considerations regarding runningductile fractures, and a depressurization case study based on recently published expansion-tube data is included.

113 citations

Journal ArticleDOI
TL;DR: In this article, the Strouhal number and drag coefficient variations with Reynolds number are documented for the two-dimensional shedding regime for elliptic cylinders, and different three-dimensional transition modes are also examined using Floquet stability analysis based on computed 2D periodic base flows.
Abstract: While the wake of a circular cylinder and, to a lesser extent, the normal flat plate have been studied in considerable detail, the wakes of elliptic cylinders have not received similar attention. However, the wakes from the first two bodies have considerably different characteristics, in terms of three-dimensional transition modes, and near- and far-wake structure. This paper focuses on elliptic cylinders, which span these two disparate cases. The Strouhal number and drag coefficient variations with Reynolds number are documented for the two-dimensional shedding regime. There are considerable differences from the standard circular cylinder curve. The different three-dimensional transition modes are also examined using Floquet stability analysis based on computed two-dimensional periodic base flows. As the cylinder aspect ratio (major to minor axis) is decreased, mode A is no longer unstable for aspect ratios below 0.25, as the wake deviates further from the standard Benard–von Karman state. For still smaller aspect ratios, another three-dimensional quasi-periodic mode becomes unstable, leading to a different transition scenario. Interestingly, for the 0.25 aspect ratio case, mode A restabilises above a Reynolds number of approximately 125, allowing the wake to return to a two-dimensional state, at least in the near wake. For the flat plate, three-dimensional simulations show that the shift in the Strouhal number from the two-dimensional value is gradual with Reynolds number, unlike the situation for the circular cylinder wake once mode A shedding develops. Dynamic mode decomposition is used to characterise the spatially evolving character of the wake as it undergoes transition from the primary Benard–von Karman-like near wake into a two-layered wake, through to a secondary Benard–von Karman-like wake further downstream, which in turn develops an even longer wavelength unsteadiness. It is also used to examine the differences in the two- and three-dimensional near-wake state, showing the increasing distortion of the two-dimensional rollers as the Reynolds number is increased.

97 citations

Journal ArticleDOI
TL;DR: Carbon capture and utilization (CCU) has attracted increased attention as a means to mitigate and adapt to climate change as discussed by the authors, which regards CO2 as a raw material and reduces CO2 emissions.
Abstract: Carbon capture and utilization (CCU) has attracted increased attention as a means to mitigate and adapt to climate change. CCU technology regards CO2 as a raw material and reduces CO2 emissions. Ho...

85 citations

Journal ArticleDOI
TL;DR: In this article, the authors focused on the cross-flow vortex-induced vibrations (VIV) of a vertical riser with a constant tension and placed in linearly sheared currents.

83 citations