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Showing 1 to 20 of 114 for “"Reynolds Stress"”.
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Reynolds stress measurements downstream of a turbine cascade
… investigation was performed to measure Reynolds stresses in the turbulent flow downstream of a large-scale linear turbine cascade. A rotatable X-wire hot-wire probe that allows redundant data to be taken with solution for mean velocities and turbulence quantities by least-squares fitting …
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Reynolds stress measurements in a turbine tip leakage vortex
… distribution and all six components of the Reynolds stress tensor. An automated probe positioning and digital signal processing system was developed to facilitate quick, accurate measurements at a large number of data points. A geared stepper-motor drive mechanism was used to rotate the …
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Computation of high-lift aerodynamics using unstructured grids and Reynolds-stress turbulence models
… lift flows and theapplication of Differential Reynolds Stress Models (DRSM).The method described in this thesis, separates the grid generation processinto two steps: generation of the anisotropic regions and isotropic grid generation.All surfaces are triangulated as part of the anisotropic grid …
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Error and uncertainty in estimates of Reynolds stress using ADCP in an energetic ocean state
The challenge of estimating the Reynolds stress in an energetic ocean environment derives from the turbulence process overlapping in frequency, or in wavenumber, with the wave process. It was surmised that they would not overlap in the combined wavenumber-frequency spectrum, due to each process …
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Error and uncertainty in estimates of Reynolds stress using ADCP in an energetic ocean state
… which are of similar magnitude to that of the Reynolds stresses.
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Turbulent Wall Eddy Structure and the Reynolds Stress Production in the Wall Region of a Pipe Flow
Made available in DSpace on 2014-12-13T18:55:27Z (GMT). No. of bitstreams: 1 7524351.pdf: 6038120 bytes, checksum: 669e6be7fd4536e411761af6f0718c59 (MD5) Previous issue date: 1975
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The evaluation of turbulence models using tensor visualization techniques
… tensor, the tensor glyph, is used to present the Reynolds stresses found in turbulent flow. Various glyph types discussed in the literature are analyzed, and a glyph suitable for the Reynolds stress tensor is developed. This glyph is constructed so that the degree of anisotropy and the orientation …
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Machine Learning and Field Inversion approaches to Data-Driven Turbulence Modeling
… need for improved closure models for the Reynolds-averaged Navier-Stokes (RANS) equations. This dissertation explores two different approaches for using experimental data to provide improved closure for the Reynolds stress tensor field. The first approach uses machine learning to learn a …
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Predictive Turbulence Modeling with Bayesian Inference and Physics-Informed Machine Learning
Reynolds-Averaged Navier-Stokes (RANS) simulations are widely used for engineering design and analysis involving turbulent flows. In RANS simulations, the Reynolds stress needs closure models and the existing models have large model-form uncertainties. Therefore, the RANS simulations are known to …
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Turbulence and macro-turbulence in the bottom boundary layer downstream of large-scale bedforms; implications for sediment transport
… of outward and inward interaction events to the Reynolds stress, downstream of large-scale bedforms, compared to those reported for uniform BBLs, are observed in the field and laboratory investigations. This induces 'abnormally' low Reynolds stress values, which are believed to invalidate the use …
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A numerical study into the effects of turbulent flows around full-scale buildings
… turbulence models were considered: a complete Reynolds stress model with two alternative proposals for the pressure-strain correlations and a k-E model used in conjunction with both linear and nonlinear stress-strain relationships. The governing differential equations were discretized using …
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A statistical jet-noise model based on the acoustic analogy and a RANS solution
… uses the information from a solution of the Reynolds-averaged Navier-Stokes equations (RANS). It evaluates the jet-noise power spectral density (PSD) in the quiescent region outside the turbulent jet. It includes the following components:1. A propagation model based on the high- and …
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Mean Force Structure and Scaling of Rough-Wall Turbulent Boundary Layers
<p>The combined roughness-Reynolds number problem is explored from the perspective of ordering of terms in the mean momentum balance. Existing mean velocity and Reynolds shear stress data from zero pressure gradient, rough-wall turbulent boundary layers are used to clarify the nature of the leading …
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Evaluation of the dynamic characteristics of the K-Gill anemometer
… measured with an error of 2%. To determine the Reynolds stress values, uw covariance and friction velocity from different methods were compared. When the stability conditions were unknown, the resulting Reynolds stress estimations have 15% relative differences between different methods.
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Numerical Investigation of turbulent coupling boundary layer of air-water interaction flow
… coupled through continuity of velocity and shear stress condition across the interface. Pseudo-spectral method is used in each flow subdomain with Fourier expansion in streamwise and spanwise directions and finite difference in vertical direction. Statistically quasi-steady flow properties, such …
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Turbulence models for non-circular ducts and channels
… turbulence models were evaluated: a complete Reynoldsstress- transport model and a two-equation k-f model used in conjunction with a nonlinear stress-strain relationship. Detailed consideration was given to the various approximations utilized in closing the Reynoldsstress equations, …
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A three-dimensional turbulent boundary layer upstream and around a junction vortex flow
… Measurements of wall static pressure, wall shear stress, mean velocity, and Reynolds stress tensor field are reported at several stations in the three-dimensional turbulent boundary layer region. Documentation of the flow edge conditions is provided as well as upstream initial conditions along a …
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Numerical modeling and simulation of compressible reacting turbulent shear layers
… are one-equation and two-equation algebraic Reynolds stress models (ASMs), which account for variations in the anisotropy of the normal stresses through modification of the pressure-strain terms of the Reynolds stress transport equations. In contrast to previous models, the compressible ASMs …
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