Breakdown of Laminar Pipe Flow into Transitional Intermittency and Subsequent Attainment of Fully Developed Intermittent or Turbulent Flow

Abraham, John; Sparrow, E. M.; Tong, Jimmy C.K.

doi:10.1080/10407790802156178

Cited by 64 publications

(56 citation statements)

References 18 publications

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“…It was later developed by the present authors in a series of studies which extended its use to internal flows, flows with adverse pressure gradients in diffusers, and pulsating flows [21][22][23][24][25][26][27][28][29][30]. Both the SST method and the newly developed transitional method rely upon a control-volume solution method wherein conservation equations are developed at a multitude of elements which constitute the solution domain.…”

Section: Fluid Dynamic Modelmentioning

confidence: 99%

Turbulent and Transitional Modeling of Drag on Oceanographic Measurement Devices

Abraham

Gorman

Reseghetti

et al. 2012

Modelling and Simulation in Engineering

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164

241

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Computational fluid dynamic techniques have been applied to the determination of drag on oceanographic devices (expendable bathythermographs). Such devices, which are used to monitor changes in ocean heat content, provide information that is dependent on their drag coefficient. Inaccuracies in drag calculations can impact the estimation of ocean heating associated with global warming. Traditionally, ocean-heating information was based on experimental correlations which related the depth of the device to the fall time. The relation of time-depth is provided by a fall-rate equation (FRE). It is known that FRE depths are reasonably accurate for ocean environments that match the experiments from which the correlations were developed. For other situations, use of the FRE may lead to depth errors that preclude XBTs as accurate oceanographic devices. Here, a CFD approach has been taken which provides drag coefficients that are used to predict depths independent of an FRE.

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Section: Fluid Dynamic Modelmentioning

confidence: 99%

Turbulent and Transitional Modeling of Drag on Oceanographic Measurement Devices

Abraham

Gorman

Reseghetti

et al. 2012

Modelling and Simulation in Engineering

Self Cite

164

241

View full text Add to dashboard Cite

show abstract

“…The transitional model used here was developed by Menter et al (2002Menter et al ( , 2004a and later used by the present authors in a series of studies that conclusively demonstrated its suitability for flows of this nature (Abraham et al, 2008Abraham and Thomas, 2009;Thomas and Abraham, 2010;Minkowycz et al, 2009;Sparrow et al, 2009;Lovik et al, 2009). …”

Section: The Computational Modelmentioning

confidence: 99%

“…The transitional model consists of transport equations for the turbulent intermittency γ , and the turbulent adjunct function which was first introduced by Menter et al (2002) and then classified in Abraham et al (2008). Those models are expressed as…”

Section: The Computational Modelmentioning

confidence: 99%

A computational method for determining XBT depths

et al. 2011

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Abstract.A new technique for determining the depth of expendable bathythermographs (XBTs) is developed. This new method uses a forward-stepping calculation which incorporates all of the forces on the XBT devices during their descent. Of particular note are drag forces which are calculated using a new drag coefficient expression. That expression, obtained entirely from computational fluid dynamic modeling, accounts for local variations in the ocean environment. Consequently, the method allows for accurate determination of depths for any local temperature environment. The results, which are entirely based on numerical simulation, are compared with the experiments of LM Sippican T-5 XBT probes. It is found that the calculated depths differ by less than 3 % from depth estimates using the standard fall-rate equation (FRE). Furthermore, the differences decrease with depth. The computational model allows an investigation of the fluid flow patterns along the outer surface of the probe as well as in the interior channel. The simulations take account of complex flow phenomena such as laminar-turbulent transition and flow separation.

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“…For the studies performed, the inlet turbulence intensity was set at 5% which is typical for pipe flows (Abraham et al, 2008). The outlet pressure was set at 20 psi.…”

Section: Wall Lubrication Forcementioning

confidence: 99%

Development and validation of a two phase CFD model for tubular biodiesel reactors

Boer

Bahri

2015

Computers & Chemical Engineering

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The use of biodiesel as an alternative to diesel has gained increasing momentum over the past 15 years. To meet this growing demand there is a need to optimise the transesterification reactor at the heart of the biodiesel production system. Assessing the performance of innovative reactors is difficult due to the liquid-liquid reaction mixture that is affected by mass transfer, reaction kinetics and component solubility. This paper presents a Computational Fluid Dynamic model of a tubular reactor developed in ANSYS CFX that can be used to predict the onset of mixing via turbulent flow. In developing the model an analysis of the reaction mixture is provided before the presentation of experimental data, which includes flow visualisation results and temperature dependant viscosity and density data for each phase. The detailed data and model development procedure represents an advancement in the modeling of the two phase transesterification reaction used in biodiesel production..

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Breakdown of Laminar Pipe Flow into Transitional Intermittency and Subsequent Attainment of Fully Developed Intermittent or Turbulent Flow

Cited by 64 publications

References 18 publications

Turbulent and Transitional Modeling of Drag on Oceanographic Measurement Devices

Turbulent and Transitional Modeling of Drag on Oceanographic Measurement Devices

A computational method for determining XBT depths

Development and validation of a two phase CFD model for tubular biodiesel reactors

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