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Showing 1 to 20 of 143 for “"Near Wall"”.
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Near-wall modeling of bubbly flows
… conditions, with special treatment at the walls, where there exist strong gradients of all variables. The present work systematically addresses the boundary conditions at solid walls for turbulent bubbly flows.
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Near-wall turbulence in the transitionally rough regime
… flow by roughness before the canonical smooth-wall turbulence is entirely altered. To study this regime, direct numerical simulations of turbulent flows over transitionally rough surfaces are conducted. First, a modulated triple decomposition of the flow is proposed to study the effect that …
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Regeneration mechanisms of organized structures in near-wall turbulence
… order to ascertain the sustenance mechanism of near-wall turbulence by investigating the mechanism of streak formation. We found the existence of streaks in quasi-2D flows thus demonstrating that contrary to many proposed theories, feedback from longitudinal flow is not necessary for streak …
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Stochastic estimation of near-wall closure in turbulence models
Linear stochastic estimation (LSE), a best mean square estimator, is used to formulate boundary closure models for the numerical large eddy simulation (LES) of turbulence. The stochastic estimation method resolves coherent structure of the wall layer using empirical correlation functions, and …
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The influence of superhydrophobic surfaces on near-wall turbulence
… condition. For texture sizes, expressed in wall units, up to $L^+ \lesssim 20$ the only effect of the surface texture on the overlying flow is through this surface slip. The direct effect of slip does not modify the dynamics of the overlying turbulence, which remains canonical and …
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Near Wall Investigation of Three Dimensional Turbulent Boundary Layers
… turbulent flows. The investigation focuses on near wall measurements in these flows. Several experimental techniques are used in the studies; however, the bulk of the investigation focuses on a three-orthogonal-velocity-component fiber-optic laser Doppler anemometer (3D-LDA) system. The control …
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Near-wall similarity in three-dimensional turbulent boundary layers
… achieved by using multi-dimensional monotone linear reconstruction procedures. Results for flow over a transonic circular arc are compared for the various time integration methods. The second topic involves an interactive adaptive remeshing algorithm. The interactive adaptive remeshing algorithm …
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Near-wall reaction effects on film-cooled surface heat transfer
… To study surface heat flux augmentation due to near-wall reactions, a shock tube experiment was employed to generate short duration, high temperature (1000-2800 K) and pressure (6 atm.) fuel-rich flows over a film-cooled flat plate. The relative increase in surface heat flux due to near-wall …
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Near-wall velocity measurements in two-dimensional turbulent boundary layers
Significant differences involving near-wall velocity profiles in two-dimensional turbulent boundary layers when such data was plotted on law of the wall coordinates were reported by D. Coles in the Stanford Conference. These discrepancies can be especially important when near-wall velocity data is …
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Near-wall similarity in two- and three-dimensional turbulent boundary layers
Static pressure, mean velocity, indirect wall shear from Preston tubes, direct wall shear using a two-dimensional (single line of action) floating element device, and direct wall shear measurements from an omnidirectional floating element capable of simultaneously determining magnitude and …
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Assessing the Near-Wall Hemodynamics in the Left Coronary Artery Using CFD
… investigate the flow mechanics and the near-wall hemodynamics associated with the different take-off angles in the left coronary artery of the human heart. From this study, we will be able to evaluate if the increase in the take-off angles of the left coronary artery will significantly …
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Near wall reaction effects on film-cooled backward-facing step heat transfer
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2003.
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Near wall high resolution particle image velocimetry and data reconstruction for high speed flows
… for measuring high speed, high magnification, near wall flow fields. Previous attempts to perform measurements such as this have been unsuccessful because of both limitations in equipment as well as proper methodology for processing of the data. This work addresses those issues and successfully …
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Characteristics of wall pressure and near-wall velocity in a flat plate turbulent boundary layer
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1988.
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Near Wall Behavior of Vortical Flow around the Tip of an Axial Pump Rotor Blade
… three-dimensional turbulent tip gap flow in a linear cascade wind tunnel with 3.3% chord tip clearance with and without moving endwall simulation. Experimental measurements have been completed in Virginia Tech low speed linear cascade wind tunnel. A 24" access laser-Doppler velocimeter (LDV) …
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Characterisation of the effective thermal conductivity in the near wall region of a packed pebble bed
… especially when considering the safety case. The wall effect present in the near-wall region affects the conduction and radiation heat transfer in this region. Various correlations and models exist to predict the effective thermal conductivity. However, most of these are only applicable to the …
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An Experimental Study of Near-Wall Turbulence Properties in Highly Drag Reduced Pipe Flows of Pseudoplastic Polymer Solutions
Made available in DSpace on 2014-12-13T18:55:38Z (GMT). No. of bitstreams: 1 7820916.pdf: 7029582 bytes, checksum: 692c2bf438064de8029607fec8446b88 (MD5) Previous issue date: 1978
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Experimental investigation of the near wall flow structure of a low Reynolds number 3-D turbulent boundary layer
… techniques were used to examine the near-wall flow structure of 2-D and 3-D turbulent boundary layers (TBLs) over a range of low Reynolds numbers. The goals of this research were (1) an increased understanding of the flow physics in the near wall region of turbulent boundary layers, …
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Experimental investigation of the effects of upstream perturbations in the near-wall and core of a high porosity random-wire porous medium.
… were positioned at two radial locations: a near-wall case, with a gap or blockage adjacent to walls of the test-section container, and a core-flow case, with a hole or a blockage at the center of the metal screens. In each case, the perturbation was for half the streamwise distance of the …
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Particulate Deposition Prediction of Diluted Two-Phase Impinging Jet
… interaction model (RANS/EIM) along with near-wall corrections, and large eddy simulation (LES) numerical approaches applied to particle-laden impinging jet flow. A new in-house tracking code for particle-laden impinging jet flow using modified EIM, as well as modified EIM in conjunction …
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