Searched for: subject:"turbulent%5C+flow"
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RAMESH KUMAR, KISHAN (author)
Optical measurement techniques are widely used in fluid mechanics to measure quantities like velocity, vorticity, and temperature. They are usually non-intrusive visualization techniques that provide a major advantage by not influencing the flow properties. Most of the developed measurement techniques estimate vorticity by computing the...
master thesis 2019
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Kaller, Thomas (author), Pasquariello, Vito (author), Hickel, S. (author), Adams, Nikolaus A. (author)
We present well-resolved large-eddy simulations of turbulent flow through a straight, high aspect ratio cooling duct operated with water at a bulk Reynolds number of Re<sub>b</sub> = 110 × 10<sup>3</sup> and an average Nusselt number of Nuxz = 371. The geometry and boundary conditions follow an experimental reference case and good agreement...
journal article 2019
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Benschop, H.O.G. (author), Greidanus, A.J. (author), Delfos, R. (author), Westerweel, J. (author), Breugem, W.P. (author)
We investigate the deformation of a linear viscoelastic compliant coating in a turbulent flow for a wide range of coating parameters. A one-way coupling model is proposed in which the turbulent surface stresses are expressed as a sum of streamwise-travelling waves with amplitudes determined from the stress spectra of the corresponding flow...
journal article 2019
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Peeters, J.W.R. (author), Rohde, M. (author)
A new friction-heat transfer analogy for the prediction of heat transfer to turbulent fluids at supercritical pressure is presented. This analogy is based on the observation that the predominent events that determine the turbulent heat flux known as hot ejections and cold sweeps have different thermophysical properties. This observation is...
journal article 2019
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Ruiter, Stijn (author)
Predicting the behavior of turbulent flows and how thermochemical properties develop such as temperature, enthalpy or concentrations is an import aspect in various fields. However, numerical calculations have a high time complexity. Therefore, models were constructed to approximate these flows. This thesis focuses on using probability density...
bachelor thesis 2018
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Toutouh, Azeddine (author)
In 1949, Toms (Toms B.A., (1949, 1977)) observed that small amounts of a drag reducing agent (DRA) could cause a considerable drag reduction in turbulent pipe flow. In application of polymer enhanced oil recovery, degradation of polymers in the supply lead could cause clogging. It was, however observed that surfactants at sufficiently high...
master thesis 2018
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Stevens, Thieu (author)
In this thesis, it is studied if the stability of a stone in a granular bed protection, can be predicted by the local output of a three-dimensional (3D) eddy resolving simulation technique.<br/><br/>In earlier studies regarding stone stability, Reynolds-Averaged Navier-Stokes (RANS) models are used to determine the loads on the bed. In the...
master thesis 2018
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Charruault, F.T. (author), Greidanus, A.J. (author), Breugem, W.P. (author), Westerweel, J. (author)
The present study introduces an experimental technique based on a Free Surface-Synthetic Schlieren (FS-SS) method in order to characterize free surfaces subjected to strong deformations. Current synthetic Schlieren methods are based on local image correlation and thus limited to rather weak image deformations, implying that they can only resolve...
conference paper 2018
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Gül, M. (author), Elsinga, G.E. (author), Westerweel, J. (author)
This paper describes the hysteresis in the torque for Taylor–Couette flow in the turbulent flow regime for different shear Reynolds numbers, aspect ratios and boundary conditions. The hysteresis increases with decreasing shear Reynolds number and becomes more pronounced as the aspect ratio is increased from 22 to 88. Measurements conducted in...
journal article 2018
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Pfeifle, Ole (author)
Curved exhaust ducts are used in aero engine applications for different purposes, including thrust vectoring, shielding of parts from the exhaust or improving stealth properties. Their integration, however, regularly represents a design problem due to flow separation and high aerodynamic losses occurring in the bend. Curved duct flows for both...
master thesis 2017
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Tian, Ye (author)
Downstream of hydraulic structures, the flow is normally of turbulence. This will cause considerable erosions on the gravel bed. To prevent this, block mattress is preferable in many cases. Its effective stabilization and feasibility on construction make it commonly used against scouring problems, protecting underwater pipelines and cables. The...
master thesis 2017
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Elsinga, G.E. (author), Ishihara, T. (author), Goudar Vishwanathappa, M. (author), da Silva, C.B. (author), Hunt, J.C.R. (author)
The scaling of turbulent motions is investigated by considering the flow in the eigenframe of the local strain-rate tensor. The flow patterns in this frame of reference are evaluated using existing direct numerical simulations of homogeneous isotropic turbulence over a Reynolds number range from up to 1131, and also with reference to data for...
journal article 2017
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Kottapalli, S. (author)
Flow induced vibrations (FIV) is a known problem in nuclear reactors. The interaction between the turbulent flow of the coolants and the fuel rod bundles generates vibrations which are undesirable. These vibrations can be a major cause of fatigue failures, stress corrosion cracking and fretting wear of materials, which lead to stand-still costs....
master thesis 2016
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Peeters, J.W.R. (author), Pecnik, R. (author), Rohde, M. (author), van der Hagen, T.H.J.J. (author), Boersma, B.J. (author)
Heated or cooled fluids at supercritical pressure show large variations in thermophysical properties, such as the density, dynamic viscosity and molecular Prandtl number, which strongly influence turbulence characteristics. To investigate this, direct numerical simulations were performed of a turbulent flow at supercritical pressure (CO2 at 8...
journal article 2016
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De Wit, L. (author)
3D CFD simulations, lab experiments and field measurements are used to get more understanding of the turbulent near field overflow dredging plume mixing. The focus has been on the most often used dredging vessel: a trailing suction hopper dredger (TSHD). Near field overflow dredging plume mixing is important because it determines the far field...
doctoral thesis 2015
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Wei, L. (author), Elsinga, G.E. (author), Brethouwer, G. (author), Schlatter, P. (author), Johansson, A.V. (author)
The Reynolds number scaling of flow topology in the eigenframe of the strain-rate tensor is investigated for wall-bounded flows, which is motivated by earlier works showing that such topologies appear to be qualitatively universal across turbulent flows. The databases used in the current study are from direct numerical simulations (DNS) of fully...
journal article 2014
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Belt, R.J. (author), Daalmans, A.C.L.M. (author), Portela, L.M. (author)
In fully developed single-phase turbulent flow in straight pipes, it is known that mean motions can occur in the plane of the pipe cross-section, when the cross-section is non-circular, or when the wall roughness is non-uniform around the circumference of a circular pipe. This phenomenon is known as secondary flow of the second kind and is...
journal article 2012
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Goudar Vishwanathappa, M. (author)
For channel flow, we explore how a hairpin eddy may reach a threshold strength required to produce additional hairpins by means of auto-generation. This is done by studying the evolution of two eddies with different initial strengths (but both below the threshold strength), initial sizes and initial stream-wise spacing between them. The...
master thesis 2012
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Nabi, M. (author)
Alluvial open channel beds often exhibit statistically periodic irregularities, known as dunes. Dunes have considerable effects on sediment transport and flow resistance. When growing during a flood, the dunes create more resistance and flood levels may rise significantly. Accurate prediction of dune properties therefore contributes to effective...
doctoral thesis 2012
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Hoan, N.T. (author)
Despite the fact that many studies on the stability of stones in bed protections under flowing water have been conducted, our knowledge is still far from advanced and reliable. Issues like how to quantify the hydraulic loads exerted on the stones on a bed and the associated stability of the stones are still central and most challenging in stone...
doctoral thesis 2008
Searched for: subject:"turbulent%5C+flow"
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